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Bulgaria and Serbia

Introduction

The mountainous Balkan Peninsula in the north is roughly bordered by the Sava and Danube rivers, in the west it runs south along the Adriatic coast past Lake Scutari (Shkoder) and further, following the coastline up to the outskirts of Thessaloniki, and then goes north to the mouth of the Danube on the coast Black Sea; in the west the Balkan Peninsula is washed by the Adriatic and Ionian seas, in the east by the Aegean, Marmara and Black seas. It is inhabited mainly by Slavs. These are the Bulgarians in the east and center, the Serbs and Croats in the west, the Slovenes in the extreme northwest, between Trieste and the Sava River. All these peoples represent the South Slavs 1
The author does not distinguish separately the Bosniaks (a part of the Serbs who converted to Islam long ago) and the Macedonians, who are quite close to the Bulgarians. (Hereinafter, except where indicated separately, editor's note.)

Other inhabitants of the Balkan Peninsula, living south of the Slavs: in the western part - Albanians, Greeks - in the center and south, and Turks in the southeast; and to the north of the Slavs - the Romanians. Separate groups of varying numbers of representatives of all these four peoples are interspersed with the Slavic population of the peninsula. But most of them live outside the Slavic territory. In turn, there is a significant Serbian population north of the Sava and Danube rivers, in Southern Hungary. The national composition and borders of residence of various peoples will be discussed in more detail later. In the meantime, we can draw the reader’s attention to the interesting fact that the name “Macedonia,” which is the heart of the Balkan Peninsula, has long been used by French gastronomes to designate a dish, the main feature of which is that its components are mixed into an inseparable whole.

Historically and geographically, of the already mentioned Slavic peoples, the Bulgarians, Serbs and Croats occupy a significantly larger territory than the Slovenes. The last ones at the beginning of the 20th century. numbered hardly more than one and a half million, they lived in the Austrian provinces of Carinthia and Carniola and for a long time were unable to form their own independent state 2
It was formed only in 1991 during the collapse of Yugoslavia.

However, with the growth of the port of Trieste and Germany's persistent attempts to expand its influence, if not subjugate the Adriatic coast, this small nation, thanks to its geographical location and anti-German (and anti-Italian) attitude, gained a certain fame and importance.

It can be said about the Bulgarians and Serbs that at that time the former controlled the eastern, and the latter, in alliance with the Greeks, the western part of the peninsula.

Each of the three nations has always sought to dominate this region, which led to endless bloody wars and the waste of large sums of money. cash, the consequence of which was hopeless poverty. If we consider the issue from a purely ethnic point of view, Bulgaria would have to receive the interior of Macedonia. Among the nationalities inhabiting it, most are Bulgarian in spirit, if not in origin, and Bulgaria, in this case, would undoubtedly establish its hegemony on the peninsula. While the center of gravity of the Serbian nation, which is ethnically justified, would move to the northwest. Political considerations, however, always conflicted with such a solution to the issue. Even if he had found a solution in this aspect, the problem of the Greek nation remained unresolved. Its presence on the European and Asian coasts of the Aegean Sea would make it absolutely impossible to delimit the boundaries of the Greek state on a purely ethnic basis. An interesting fact: the Slavs, who dominated the interior of the peninsula and partly on its eastern and western coasts, never tried to take possession of the Aegean coast and the cities located there. The Adriatic remained the only sea, besides the Black Sea, on the coast of which the Balkan Slavs settled. In this regard, only the interior parts of the peninsula were Slavic, while the coastal areas were controlled by the Greeks, who were equal in number to all three Slavic peoples. It's inevitable that final decision controversial issue and the definition of state boundaries could be sought along the path of territorial compromise.

Balkan Peninsula in ancient times 400 BC. e. – 500 AD e.

In ancient times, the entire eastern part of the Balkan Peninsula between the Danube and the Aegean Sea was called Thrace, the western part (41° north latitude) was called Illyria; in the lower reaches of the Vardar River (ancient Aksiy) 3
And now this river in its lower reaches and up to its mouth (flowing through the territory of Greece) is called Axios.

Located in Macedonia. Data on the names of tribes and personal names of the Illyrians and Thracians have been preserved. Philip II, king of Macedonia (reigned 359–336 BC), conquered Thrace in the 4th century. BC e. and in 342 BC. e. founded the city of Philippopolis 4
On the site of the city of Eumolpiada that existed here.

The first campaign of Alexander the Great was aimed at consolidating his dominance on the peninsula, but in the 3rd century the Celts, who had previously passed through Illyria, invaded Thrace from the north and devastated it. The Celts left at the end of the same century, and the place names that have survived from that time indicate the path they took. The city of Belgrade until the 7th century. was known by the Celtic name Singidunum. It is possible that modern Niš, formerly Nais, is based on a Celtic name. By 230 BC. e. refers to the first contacts of Ancient Rome with Illyria, which were led by the pirate inclinations of its inhabitants. But for a long time, Rome controlled only the Dalmatian coast, named after the Illyrian Dalmatian tribe. This was due to the mountainous nature of the Illyrian landscape. Several mountain ranges, almost without interruption, stretched parallel to each other along the entire Adriatic coast, forming a natural obstacle to invasion from the west. The interior of the peninsula gradually began to be conquered by the Romans after they arrived in 146 BC. e. finally conquered Macedonia. Throughout the 1st century. BC e. Conflicts broke out with varying success between the conquerors and local tribes occupying the territory from the Adriatic coast to the Danube. They were attacked both from Aquileia from the north and from Macedonia from the south, but only at the very beginning of the 1st century the Danube became the border of the Roman Empire.

In 6, Moesia, which occupied most of the Serbian kingdom of the early 20th century and the northern half of the Balkan kingdom, located between the Danube and the Carpathians 5
Captured by Rome in 29–27. BC e. during the campaign of Crassus, in 15 AD. e. provincial government introduced.

(ancient Hemus), became a province of the Roman Empire 6
The name Carpathians comes from the Indo-European “kar” - “ker”, which means “stone”, “rocky place”, etc. Already in Roman times the Carpathians were called that way. They were also called the Sarmatian Mountains.

Twenty years later, Thrace, located between the Carpathians and the Aegean coast, became part of the empire and became a province under Emperor Claudius in 46. The province of Illyria, also called Dalmatia, extended from the Sava River to the Adriatic coast, the province of Pannonia was located between the Danube and Sava . In 107, Emperor Trajan finally conquered the Dacians, who inhabited the lands on the lower Danube, and formed the province of Dacia on an area approximately equal in area to modern Wallachia and Transylvania. The Roman domination of this transdanubian territory lasted for no more than 150 years, but the entire territory stretching from the Adriatic to the Danube delta flowing into the Black Sea was repeatedly Romanized. Emperor Trajan is called by historians “Charlemagne of the Balkan Peninsula”; everything here reminds us of him, and his reign marked the zenith of the power of the Roman Empire in this part of the world. The Balkan Peninsula enjoyed the benefits of Roman civilization for three centuries, from the 1st to the 4th centuries, but since the 2nd century the Romans were much more likely to take up defensive positions than to attack. The war of Emperor Marcus Aurelius against the Marcomanni in the second half of the 2nd century. became a turning point. Rome still won victories, but no more territories were added to the empire. In the 3rd century. Germanic tribes rushed south, they came to the place of the Celts. Goths 7
As well as the tribes of the Northern Black Sea region allied to them, from the Scythians and Sarmatians to the Slavs and others.

They invaded the peninsula, and in 251 Emperor Decius was killed in battle with them near Odessus (modern Varna), a city on the Black Sea coast. 8
The Battle of Abritto took place further north, in Dobruja, in a marshy area.

The Goths then penetrated into the vicinity of Thessaloniki, but were defeated by Emperor Claudius at Nais in 269; however, soon after this, Emperor Aurelian was forced to cede Dacia to them. Emperor Diocletian, originally from Dalmatia, who reigned from 284 to 305, carried out a reform of government. The boundaries of the provinces were changed, 12 dioceses were formed, which in turn were divided into provinces. Under Constantine (reigned 306–337), several dioceses were united into a prefecture (there were 4 prefectures in total). Pannonia and Illyricum (including Dalmatia) went to the Prefecture of Italy, Thrace to the Prefecture of the East, while the entire central part of the peninsula became part of the Prefecture of Illyria with its capital at Thessaloniki. The areas north of the Danube were lost; what is now Western Bulgaria became known as the diocese of Dacia, and Moesia—the modern kingdom of Bulgaria—shrank in size and became part of the diocese of Thrace. The southern part of Dalmatia, that is, modern Montenegro, was transferred to the diocese of Illyricum.

In 325, an important event occurred that had far-reaching consequences - Constantine the Great founded the capital of the empire on the site of the Greek colony of Byzantium. In the same century, the Huns invaded Europe from Asia. In 375, crossing the Don River, they defeated first the Alans and then the Ostrogoths, who settled between the Dnieper and the Dniester, and the Visigoths, who inhabited Transylvania and modern Romania, moved south as a result of this event. Emperor Valens died in 378 in the battle with the Visigoths at Adrianople (a city founded by Emperor Hadrian in the 2nd century in Thrace). The emperor of Theodosius who replaced him tried to pacify them with gifts and placed them as guards on the northern border. But after the death of the emperor in 395, the Goths invaded the Balkan Peninsula and devastated it, after which they headed to Italy. After the death of Theodosius, the empire was divided and never became a single entity again. The border between the two parts of the empire ran along the border we have already mentioned, dividing the prefecture of Italy and the prefecture of Illyria (on the Balkan Peninsula) and the East (in North Africa - between the diocese of Egypt, which belonged to the prefecture of the East, and the diocese of Africa, which was part of the prefecture of Italy). That is, it began in the south on the Adriatic coast near the Bay of Kotor and went north along the Drina valley until the confluence of the latter with the Sava.

It will become clear later that this section had consequences that were felt right up to today. In short, the Western Roman Empire was Latin in language and character, while the Eastern was Greek, although owing to the military importance to Rome of the Danube provinces and the close relations between them, the Latin influence in them was for a long time stronger than the Greek. This influence is confirmed by the example of modern Romania, whose people were partly, and whose language was largely formed, in confrontation with the Roman legionaries of Trajan and their Latin language.

Latin influence in shipping, settlement building and art on the shores of the Adriatic Sea was overwhelming, Greek culture dominated the Black Sea coast. Even in the language of the Albanians, descendants of the ancient Illyrians, which has a meager vocabulary, up to one quarter of Latin borrowings are found. Despite the fact that the ancestors of the Albanians were pushed out from the north by the Romans and from the south by the Greeks, they still live in their mountain strongholds, immune to influence from other civilizations.

Christianity spread to the coasts of the peninsula very early; Macedonia and Dalmatia were the areas where it was established first. It took some time for it to penetrate deep into the peninsula. During the reign of Diocletian, many Christian martyrs suffered for their faith in the Danube provinces, but with the accession of Constantine the Great to the throne, the persecution ceased. However, as soon as the Christians were left to their own devices, they began to persecute each other, and in the 4th century the entire peninsula was shaken by Arian disputes.

In the 5th century the Huns moved from the shores of the Black Sea and reached the plains of the Danube and Tisza; they devastated the Balkan Peninsula, despite the payment by Constantinople of the tribute they imposed on it in exchange for their promise to make peace. In 453, after the death of Attila, the Huns returned to Asia again 9
After a heavy defeat in the battle on the Catalaunian fields (west of the modern city of Troyes in France) in 451, where, according to the Gothic historian of the 6th century. Jordan, up to 200 thousand soldiers fell on both sides, Attila’s failure in Italy and his absurd death on the wedding bed with his next wife, in 454 the Huns were completely defeated by the Gepids and other peoples who rebelled against their rule, after which they were soon completely destroyed in the Northern Black Sea region there were other waves of nomads invading here from the East.

And in the second half of this century, the Goths dominated the peninsula. Theodoric captured Singidunum (modern Belgrade) in 471 and, having plundered Macedonia and Greece, in 483 settled in the city of Nova (modern Svishtov in Bulgaria) on the lower Danube, from where ten years later he headed to Italy. At the end of the century, the Huns returned to the lower Danube and made several devastating raids on the peninsula, reaching Epirus and Thessaly.

The arrival of the Slavs on the Balkan Peninsula 500-650.

The Balkan Peninsula, which during the reign of the Romans achieved unprecedented prosperity and ensured a safe existence for itself, gradually began to plunge into a barbaric state as a result of endless invasions and raids. Cities protected by fortress walls, such as Thessaloniki, Constantinople and others, were the only safe place, and all the lands surrounding them turned into deserted wastelands. This situation persisted for three centuries. Two conclusions could be drawn from this: either these lands had an unprecedented ability to quickly recover, and therefore they were plundered so often, or, what seems more plausible, after a while there was simply nothing left that could be plundered. That is why the reports of Byzantine chroniclers about the huge number of prisoners and captured trophies are clearly exaggerated.

It is impossible to count how many times waves of invasions swept across the unfortunate peninsula, leaving behind a devastated territory. The emperors and their commanders did everything possible that was in their power: they built defensive structures on the borders, carried out punitive expeditions, and tried to quarrel among themselves the hordes of barbarians. But they had to defend an empire that stretched from Armenia to Spain, and it is not surprising that, despite their best efforts, they were not always successful. The growing wealth of Constantinople and Thessaloniki irresistibly attracted wild tribes from the east and north. Unfortunately, Greek citizens were more likely to waste their energy on theological debates and spend their free time in the circus rather than stand up for the country's defense. Only thanks to large cash payments to enemies ready to invade the country, the Greeks managed to protect their coast from them. The departure of the Huns and Goths opened the way for new unwanted visitors. In the VI century. Slavs appear on the peninsula for the first time. They came from their homeland north of the Carpathians in Galicia and Poland, and possibly also from what is now Hungary. Their path ran to the south and southeast. Presumably they had visited Dacia, the lands north of the Danube, in the previous century, but the Slavs are first mentioned when they crossed that river during the reign of Emperor Justin I (518–527). These were scattered tribes without any single leader or central authority. Some say that they were driven only by the instinct of anarchy, others claim that they carried within them the ideals of democracy. We can only say with certainty that they had neither the institution of leaders nor initiative developed, and there was no cohesion and organization. Eastern Slavs, the ancestors of the Russians, were only at the stage of formation of their community, while the Scandinavians (Varangians), adventurers, in relatively smaller numbers, came to Kyiv and began to rule there. The South Slavs were similarly incapable of forming an independently united community, setting a specific goal for themselves and achieving it. 10
The Slavs had strong tribal associations, they had talented leaders who skillfully led them in battles, well described by Eastern Roman historians (Procopius of Caesarea, Mauritius, Foephylact Simocattus). The first invasion of the Slavs, who defeated 15 thousand. army of the empire, recorded in 499. In the battle on the river. Tsutra in Thrace, the Eastern Roman army lost 4 thousand soldiers killed and drowned.

The Slavs invaded the Balkan Peninsula not alone, but together with the Avars 11
The Slavs had been invading the empire for several decades before the arrival of the Avars.

A terrible, feared people who, like the Huns, came from Asia (from the Turks or Mongols). These invasions occurred with increasing frequency during the reign of Emperor Justinian I (527–565) and culminated in 559 with a large joint offensive of all the tribes under the command of a certain Zabergan against Constantinople. The famous Byzantine commander Belisarius won a brilliant victory over them. The Avars were a nomadic tribe, and the horse was their natural means of transportation. The Slavs walked 12
The Slavs were excellent horsemen (as well as infantrymen).

And, apparently, the more experienced Asians used them as infantry in their military campaigns. The Avars, whose numbers are believed to be significantly smaller than the Slavs, settled in Pannonia, where Attila and the Huns had been located more than a century earlier. The Avars were located north of the Danube, although they constantly invaded Upper Moesia - modern Serbia. The Slavs, whose numbers were undoubtedly very significant, gradually settled throughout the entire territory south of the Danube. The agricultural lands here have become deserted and depopulated as a result of endless invasions. In the second half of the 6th century. all military efforts of Constantinople were directed towards Persia 13
Until 1935, it was customary to call Iran this way in countries Western Europe, in Russia and the USA. Since 1935, at the request of the Iranian government, the country began to be officially called Iran.

So any invader who invaded the Balkan Peninsula had every advantage. It was during this period that the Avars reached the peak of their power. They became masters of the entire country, right up to the walls of Adrianople and Thessaloniki, although they did not settle there. The peninsula appears to have been colonized by the Slavs, who also penetrated into Greece. But all this time the Avars were the dominant and guiding force in both the political and military spheres. During the Second Persian War, which broke out in 622. 14
There were many Iranian-Byzantine wars - the war of 502–506; war 527–532; multiple clashes in Lazika (Colchis, modern Western Georgia), ending with " eternal peace"in 562; war 572–591 and, finally, the war of 602 (sometimes written 604) - 628, which ended with a peace treaty in 629. During this last war, the parties completely exhausted each other, after which the Arabs entered the historical scene, destroyed Iran by 651 and conquered the most valuable lands of the empire in the Middle East and North Africa, which besieged Constantinople three times (in 668-669, 673-678, 717-718).

And resulting in the long absence of the emperor in Constantinople, the Avars, not satisfied with the tribute received from the Greeks, entered into an alliance with the Persians. In 626, a large combined army of Slavs and Asian tribes attacked Constantinople by sea and land from the European side, while the Persians threatened the city from Asia. But the walls of Constantinople and the ships of the Greeks turned out to be an insurmountable barrier for the enemy. Discord began between the Slavs and the Avars, and both of them, saving themselves, turned into a shameful and hasty flight.

After these events, nothing more was heard about the Avars on the Balkan Peninsula, although their power was finally crushed by Charlemagne in 799. In Russia, the fall of the Avars became a proverb: “perished like a doom.” But the Slavs remained. During these turbulent years, their penetration deep into the Balkan Peninsula took place gradually, and by the middle of the 7th century. it has ended. The main flows of Slavic immigration went in the southern and western directions. The Slavs, moving south, settled the lands between the Danube and the Balkan Mountains, advanced into Macedonia and penetrated into Greece. Southern Thrace in the east and Albania in the west were affected to a minor extent by the resettlement, and in these areas the local population remained. Beyond the Aegean coast and major cities on or near it the Greeks retained control, and those Slavs who found themselves in Greece were soon assimilated by the local population. A more powerful flow of Slavs, which moved west and then northwest, passed through the entire country, reached the shores of the Adriatic Sea and went deeper into the Alps, reaching the sources of the Sava and Drava. From this point in the west to the shores of the Black Sea in the east, the entire territory was inhabited by the Slavs, a similar situation has survived to this day. Small groups of Slavs who found themselves in Dacia, north of the Danube, were gradually assimilated by the local population of that province, who were descendants of Roman soldiers and colonists and the ancestors of modern Romanians. The fact that the Slavic influence here was significant is proven by the presence of many Slavic words in the Romanian language.

Geographic names are reliable evidence of the deep influence of Slavic immigration. The Greek and Roman names of places along the entire coast from the mouth of the Danube and on the Adriatic were given their own names by Slavic settlers. The fewest Slavic place names were found in Thrace, especially in its southeastern part, and in Albania. In Macedonia and Lower Moesia (Bulgaria) very few names from ancient times survive, while in Upper Moesia (Serbia) and the interior of Dalmatia (Bosnia, Herzegovina and Montenegro) they have completely disappeared. The Slavs, although their tribal names were known, the Greeks until the 9th century. usually called by the common name "sklavina" (Greek"sklabeni")

In the 7th century, starting with the defeat of the Slavs and Avars under the walls of Constantinople in 626 and the final victory of the emperor over the Persians in 628, the influence and power of the Greeks began to revive throughout the peninsula and up to the Danube. This process coincided with the decline of the former power of the Avars.

It was the custom of the cunning Byzantine diplomacy to speak of the lands seized by various barbarian tribes as a gift granted to them thanks to the generosity of the emperor; the leaders of these tribes were awarded magnificent titles and provided them with large incomes, inciting envy between them towards each other; detachments of Slavic mercenaries were also accepted into the imperial army. The supremacy of Constantinople was again restored more effectively than if it had been won by force all along.

), etc.

By the end of the 4th century BC, the Greek language and culture dominated not only the Balkans, but also around the entire Eastern Mediterranean. At the end of the 6th century BC, the Persians invaded the Balkans and then moved on to the fertile regions of Europe. Parts of the Balkans and more northern areas were ruled by the Achaemenid Persians for some time, including Thrace, Paeonia, Macedon, and most of the Black Sea coastal areas of Romania, Ukraine and Russia. However, the outcome of the Greco-Persian Wars meant that the Achaemenids were forced to give up most of their European territories.

Berlin Congress

The results were initially regarded as a great achievement in the field of peacekeeping and stabilization. However, most of the participants were not entirely satisfied, and complaints about the results bled until they exploded into a world war in 1914. Serbia, Bulgaria and Greece made progress, but far less than they thought they deserved. The Ottoman Empire, at the time called the "sick man of Europe" was humiliated and significantly weakened, making it more prone to internal unrest and more vulnerable to attack. Although Russia had already won the war that prompted the conference, he was humiliated in Berlin, and resented his treatment. Austria gained large territory, which angered the South Slavs and led to decades of tension in Bosnia and Herzegovina. Bismarck became the object of hatred among Russian nationalists and Pan-Slavists, and found that he had tied Germany too close to Austria in the Balkans.

In the long term, tensions between Russia and Austria-Hungary increased, as did the question of nationality in the Balkans. The Congress was directed to revise the Treaty of San Stefano and keep Constantinople in Ottoman hands. He effectively disavowed Russia's victory over the crumbling Ottoman Empire in the Russo-Turkish War. The Berlin Congress returned to the territory Ottoman Empire that the previous treaty gave to the Principality of Bulgaria, primarily Macedonia, thus creating a strong revanchist demand in Bulgaria, which in 1912 was one of the many causes of the First Balkan War.

20th century

Balkan traditional clothing, c. 1905

Balkan wars

The Balkan Wars were two wars that took place in the Balkans in 1912 and 1913. Four Balkan states were defeated by the Ottoman Empire in the first war; one of the four, Bulgaria, was defeated in the second war. The Ottoman Empire lost almost all of its reserves in Europe. Austria-Hungary, although not at war, was weakened by a greatly enlarged Serbia insisting on the unification of the South Slavic peoples. The war laid the groundwork for the Balkan crisis of 1914, and was thus "the prelude to the First World War."

First World War

Coming of the 1914 War

The monumentally colossal First World War was ignited by a spark in the Balkans when a Bosnian Serb named Gavrilo Princip assassinated the heir to the Austrian throne, Franz Ferdinand. Princip was a member of a Serbian fighting group called Crna Ruka (Serbian for "Black Hand"). Following the assassination, Austria-Hungary sent an ultimatum to Serbia in July 1914 with certain provisions mainly aimed at preventing Serbian compliance. When Serbia only partially complied with the terms of the ultimatum, Austria-Hungary declared war on Serbia on July 28, 1914.

Many members of the Austro-Hungarian government, such as Konrad von Hötzendorf, had been hoping to provoke war with Serbia for several years. They had several motives. In part they feared the power of Serbia and its ability to sow dissent and disruption in the provinces of the "South Slavic" empire under the banner of a "more Slavic state". Another hope is that they could annex Serbian territories in order to change the ethnic composition of the empire. With a large number of Slavs in the empire, some in the German-dominated half of the government hoped to balance the power of the Magyar-dominated Hungarian government. Until 1914, more peaceful elements were unable to object to these military strategies, either through strategic considerations or political ones. However, Franz Ferdinand, the leading proponent of a peace settlement, was removed from the scene, and the more hawkish elements were able to achieve victory. Another factor in this is the development of Germany giving the Dual Monarchy a "blank check" to pursue a military strategy that secured German support.

Austro-Hungarian planning for operations against Serbia was not extensive, and they encountered many technical difficulties in mobilizing the army and launching operations against the Serbs. They faced problems with train schedules and mobilization schedules that conflicted with agricultural cycles in some areas. When operations began in early August, Austria-Hungary failed to suppress the Serbian armies, as many in the monarchy had predicted. One of the difficulties for the Austro-Hungarians was that they had to divert many units north to counter the Russian advance. The planning of operations against Serbia did not include a possible Russian intervention, which would have been expected to pit Germany against the Austro-Hungarian army. However, the German army had long planned to attack France before turning to Russia in view of the war powers with the Entente. (Cm: Schlieffen plan) Poor communication between the two governments led to this disastrous oversight.

Fighting in 1914

As a result, Austria-Hungary's war effort was damaged almost to ransom within a few months of the start of the war. The Serbian army, which was approaching from the south of the country, met the Austrian army in the Battle of Cer beginning on August 12, 1914.

The Serbs were placed in defensive positions against the Austro-Hungarians. The first attack was on August 16, between units of the 21st Austro-Hungarian Division and parts of the Serbian combined division. In a harsh night battle, the battle ebbed and flowed until the Serbian line rallied under the leadership of Stjepa Stepanović. Three days later the Austrians retreated across the Danube, suffering 21,000 casualties to 16,000 Serbian casualties. This is the first Allied victory in the war. The Austrians did not achieve their goal main goal liquidation of Serbia. In the next couple of months the two armies fought major battles on the Drina (6 September to 11 November) and at Kolubara from 16 November to 15 December.

In the autumn, with many Austro-Hungarians tied up in heavy fighting with Serbia, Russia was able to make huge raids into Austria-Hungary, capturing Galicia and destroying much of the Empire's fighting capacity. It was not until October 1915, with large amounts of German, Bulgarian and Turkish aid, that Serbia was finally occupied, although the weakened Serbian army retreated to Corfu with Italian assistance and continued the fight against the central authorities.

With the help of Italy, they managed to conquer Yugoslavia within two weeks. They then joined forces with Bulgaria and invaded Greece from the Yugoslav side. Despite Greek resistance, the Germans took advantage of the presence of the Greek army in Albania against the Italians to advance into Northern Greece and consequently conquer the entire country within 3 weeks, with the exception of Crete. However, even with stiff Cretan resistance, which cost the Nazis much of their elite landing forces, the island capitulated after 11 days of fighting.

In May 1, the Balkan borders were once again mixed with the creation of several puppet states, such as Croatia and Montenegro, Albanian expansion into Greece and Yugoslavia, Bulgarian annexation of territories of the Greek North, creation of a Vlach state in the Greek Pindus Mountains and annexation of all the Ionian and part of the Aegean islands to Italy.

With the end of the war, the changes in ethnic composition returned to the original conditions and the settlers returned to their native lands, mainly those settling in Greece. The Albanian population of the Greek North, the kulaks, were forced to leave their lands because they collaborated with the Italians. There were about 18,000 in 1944.

Consequences of World War II

On January 7–9, 1945, Yugoslav authorities killed several hundred claimed Bulgarians in Macedonia as collaborators, in an event known as "Bloody Christmas".

Religious persecution has occurred in Bulgaria, targeting Christian Orthodox, Catholic and Protestant churches, as well as Muslim, Jewish and others in the country. The antagonism between the communist state and the Bulgarian Orthodox Church improved somewhat after Todor Zhivkov became the leader of the Bulgarian Communist Party in 1956. Zhivkov even used the Bulgarian Orthodox Church for the purpose of his politics.

Post-communism

The late 1980s and early 1990s brought the collapse of communism in Eastern Europe. As Westernization spread through the Balkans, many reforms were introduced, leading to the introduction of a market economy and privatization, among other capitalist reforms.

In Albania, Bulgaria and Romania, the change in the political and economic system was accompanied by a period of political and economic instability and tragic events. The same was true in most of the former Yugoslav republics.

Yugoslav wars

The collapse of the Yugoslav federation was due to various factors in the various republics that comprised it. In Serbia and Montenegro, there were attempts by various factions of the old party elite to maintain power in the new conditions along and an attempt to create a Greater Serbia by keeping all Serbs in one state. In Croatia and Slovenia, multi-party elections produced a nationally inclined leadership, then followed in the footsteps of their earlier communist predecessors and oriented towards capitalism and secession. Bosnia and Herzegovina was divided between the conflicting interests of its Serbs, Croats and Bosniaks, with Macedonia largely trying to stay out of the conflict.

The outbreak of violence and aggression came as a consequence of unresolved national, political and economic issues. The conflicts have resulted in the deaths of many civilians. The real start of the war was a military attack on Slovenia and Croatia to take over the Serb-controlled JNA. Before the war, the JNA began to accept volunteers driven by the ideology of Serbian nationalists seeking to realize their nationalist goals.

The ten-day war in Slovenia in June 1991 was short and with few casualties. However, the Croatian War of Independence in the second half of 1991 brought many casualties and much damage to Croatian cities. As the war eventually died down in Croatia, the war in Bosnia and Herzegovina began in early 1992. Peace came only in 1995 after events such as the Srebrenica massacre, Operation Storm, Operation Mistral 2 and the Dayton Agreement, which provided for a temporary decision, but nothing was finally decided.

The economy suffered enormous damage throughout Bosnia and Herzegovina and in the affected areas of Croatia. The Federal Republic of Yugoslavia also suffered economic difficulties under internationally imposed economic sanctions. In addition, many large historical cities were destroyed by wars, for example Sarajevo, Dubrovnik, Zadar, Mostar, Sibenik and others.

The wars caused large migrations of people, mostly involuntarily. With the exception of its former republics of Slovenia and Macedonia, the settlement and national composition of the population in all parts of Yugoslavia changed dramatically, due to the war, but also political pressure and threats. Because it was a conflict fueled by ethnonationalism, people of ethnic minorities usually fled to regions where their ethnicity was in the majority. Since the Bosniaks had no immediate refuge, they were perhaps the most affected by ethnic violence. The United Nations tried to create safe areas for the Bosniak population of eastern Bosnia, but in cases such as Srebrenica, peacekeeping troops (Dutch forces) are unable to protect safe areas, leading to the massacre of thousands. As Dayton ended the war in Bosnia, fixing the borders between the warring sides to roughly those established in the fall of 1995, one immediate result of population movements following the peace treaty was a sharp decline in ethnic violence in the region. A number of commanders and politicians, notably Serbia's former president Slobodan Milosevic, were put on trial by the UN International Criminal Tribunal for the Former Yugoslavia for a number of war crimes - including deportations and genocide - that took place in Bosnia and Herzegovina and Kosovo, Croatia's former president Franjo Tudjman and Bosnia's Alija Izetbegovic died before the alleged charges were brought against them at the ICTY. Slobodan Milosevic died before the trial could be concluded.

The first disruptions in Kosovo did not escalate into war until 1999, when the Federal Republic of Yugoslavia (Serbia and Montenegro) bombarded NATO for 78 days with Kosovo becoming a protectorate of international peacekeeping forces. Massive and systematic deportation of ethnic Albanians occurred during the Kosovo War in 1999, with more than one million Albanians (out of a population of approximately 1.8 million) forced to leave Kosovo. This was quickly undone from the consequences.

2000 to present

Greece has been a member of the European Union since 1981. Greece is also an official member of the Eurozone, and the Western European Union. Slovenia and Cyprus have been members of the EU since 2004, and Bulgaria and Romania joined the EU in 2007. Croatia joined the EU in 2013. North Macedonia also received candidate status in 2005 under its then provisional name Former Yugoslav Republic of Macedonia, while while other Balkan countries have expressed a desire to join the EU, but at some date in the future.

Greece has been a member of NATO since 1952. In 2004, Bulgaria, Romania and Slovenia became members of NATO. Croatia and Albania joined NATO in 2009.

In 2006, Montenegro separated from the state of Serbia and Montenegro, also making Serbia a separate state.

On 17 October 2007, Croatia became a non-permanent member of the United Nations Security Council for the 2008–2009 term, while Bosnia and Herzegovina became a non-permanent member for the 2010–2011 period.

Kosovo declared independence from Serbia on February 17, 2008.

After the economic crisis of 2008, former Yugoslav countries began to cooperate at levels that were similar to those in Yugoslavia. The term "" was coined The Economist after the regional train "Cargo 10" was created.

Review of State Histories

Greece:
Bulgaria: The Bulgars, a Turkic tribe, settled in the Balkans after 680. They are subsequently absorbed by the local Slavs. Bulgaria Christianized at the end of the 9th century. The Cyrillic alphabet developed around the Preslav literary school in Bulgaria in the early 10th century. The Bulgarian Church was recognized as autocephalous during the time of Simeon the Great, who greatly expanded the state over Byzantine territory. In 1018, Bulgaria became an autonomous subject of the Roman Empire until the restoration by the Asen dynasty in 1185. In the 13th century, Bulgaria was once again one of the powerful states in the region. By 1422, all Bulgarian lands south of the Danube had become part of the Ottoman state, however local administration remained in Bulgarian hands in many places. North of the Danube, Bulgarian boyars continued to rule for the next three centuries. Bulgarian continued to be used as the official language north of the Danube until the 19th century.
Serbia: After the settlement of the Slavs, the Serbs established several principalities, as described in the DAI. Serbia was established as a kingdom in 1217, and an empire in 1346. By the 16th century, the entire territory of modern Serbia was annexed by the Ottoman Empire, at times interrupted by the Habsburg Empire. At the beginning of the 19th century, the Serbian revolution restored the Serbian state, pioneering the elimination of feudalism in the Balkans. Serbia became the region's first constitutional monarchy and later expanded its territory in wars. The former Habsburg crownland of the Vojvodina united with the Kingdom of Serbia in 1918. After World War I, Serbia formed Yugoslavia with other South Slavic nations, which existed in several forms until 2006, when the country gained its independence.
Croatia: Following the settlement of the Slavs in the Roman provinces of Dalmatia and Pannonia, Croatian tribes created two duchies. They were surrounded by the Franks (and later Venetians) and Avars (and later Hungarians), while the Byzantines tried to maintain control of the Dalmatian coast. The Kingdom of Croatia was founded in 925. It covers parts of Dalmatia, Bosnia and Pannonia. The state came under papal (Catholic) influence. In 1102, Croatia entered into an alliance with Hungary. Croatia is still considered a separate, albeit vassal kingdom. With the Ottoman conquest of the Balkans, Croatia fell after successive battles, completed in 1526. The remainder then received Austrian rule and protection. Most of the border areas became part of the Military Frontier, inhabited and defended by Serbs, Vlachs, Croats and Germans, since the area had previously been depopulated. Croatia joined Yugoslavia in 1918-20. Independence was maintained after the Croatian War.
Albania: Proto-Albanians, probably a conglomerate of Illyrian tribes who resisted assimilation with the latest waves of migrations to the Balkans. Kingdom of Ardiaean, with its capital at Scodra, perhaps best example centralized ancient Albanian state. After several conflicts with the Roman Republic, building up to the Third Illyrian War, Ardiaean, as well as much of the Balkans, was brought under Roman rule for many centuries to come. Its last ruler, King Gentius, was captured in 167BC in Rome. After the collapse of the Western Roman Empire, the territory that is today Albania remained under Byzantine control until the Slavic migrations. It was incorporated into the Bulgarian kingdom in the 9th century. The territorial core of the Albanian state formed in the Middle Ages, as the Principality of Arber and the Kingdom of Albania. The first records of these Albanian people as a separate ethnicity also refer to this period. Most of the coast of Albania was controlled by the Venetian Republic from the 10th century until the arrival of the Ottoman Turks (Albania Veneta), while the interior was ruled by the Byzantines, Bulgarians or Serbs. Despite the long resistance of Skanderbeg, the area was captured in the 15th century by the Ottoman Empire and remained under their control as part of the Rumelia province until 1912, when the first independent Albanian state was declared. The formation of an Albanian national consciousness dates back to the late 19th century and is part of the wider phenomenon of rising nationalism within the Ottoman Empire.
Montenegro: In the 10th century there were three principalities on the territory of Montenegro: Duklja, Travunia and Serbia ("Raška"). In the mid-11th century, Duklje gained independence through a revolt against the Byzantines; The Vojislavljević dynasty ruled as Serbian monarchs, taking over the territories of the former Serbian principality. It then came under the rule of the Nemanjic dynasty of Serbia. By the 13th century, Zeta replaced Dukl When we're talking about about the kingdom. At the end of the 14th century, southern Montenegro (Zeta) came under the rule of the noble Balšić family, the Chernojevics, and by the 15th century, Zeta was more commonly called Crna Gora (

Did you know What is a thought experiment, gedanken experiment?
This is a non-existent practice, an otherworldly experience, an imagination of something that does not actually exist. Thought experiments are like waking dreams. They give birth to monsters. Unlike a physical experiment, which is an experimental test of hypotheses, a “thought experiment” magically replaces experimental testing with desired conclusions that have not been tested in practice, manipulating logical constructions that actually violate logic itself by using unproven premises as proven ones, that is, by substitution. Thus, the main task of the applicants of “thought experiments” is to deceive the listener or reader by replacing a real physical experiment with its “doll” - fictitious reasoning on parole without the physical verification itself.
Filling physics with imaginary, “thought experiments” has led to the emergence of an absurd, surreal, confused picture of the world. A real researcher must distinguish such “candy wrappers” from real values.

Relativists and positivists argue that “thought experiments” are a very useful tool for testing theories (also arising in our minds) for consistency. In this they deceive people, since any verification can only be carried out by a source independent of the object of verification. The applicant of the hypothesis himself cannot be a test of his own statement, since the reason for this statement itself is the absence of contradictions in the statement visible to the applicant.

We see this in the example of SRT and GTR, which have turned into a kind of religion that governs science and public opinion. No amount of facts that contradict them can overcome Einstein’s formula: “If a fact does not correspond to the theory, change the fact” (In another version, “Does the fact not correspond to the theory? - So much the worse for the fact”).

The maximum that a “thought experiment” can claim is only the internal consistency of the hypothesis within the framework of the applicant’s own, often by no means true, logic. This does not check compliance with practice. Real verification can only take place in an actual physical experiment.

An experiment is an experiment because it is not a refinement of thought, but a test of thought. A thought that is self-consistent cannot verify itself. This was proven by Kurt Gödel.

UDC 621.396.677.71

DOI: 10.14529/ctcr150203

CYLINDRICAL SLOT ANTENNA

D.S. Klygach, V.A. Dumchev, N.N. Repin, N.I. Voitovich

South Ural State University, Chelyabinsk

A slotted cylindrical antenna with an original device for matching with the feeder is presented. The antenna is made in the form of a longitudinal slot on a metal pipe with a diameter much smaller than the wavelength; the slit length is less than the wavelength in free space. The antenna parameters were found using a numerical method in a strict electrodynamic formulation of the problem. At the same time, the design of the matching device is taken into account in the electrodynamic model of the antenna. The theoretical results in the operating frequency range are in good quantitative agreement with the experimental results obtained on antenna prototypes. The method and device proposed in the article make it possible to simply and conveniently coordinate the antenna with the feeder.

Key words: slot antenna, matching band, SWR.

Introduction

The slot cylindrical antenna was first proposed in 1938 by Alan D. Blumlein for use in television broadcasting in the ultrashort wave range with horizontal polarization and a circular radiation pattern (RP) in the horizontal plane. Slot antennas do not disrupt the aerodynamics of the objects on which they are installed, which later determined their widespread use in submarines, airplanes, missiles and other moving objects. Slot antennas are also widely used as terrestrial antennas.

In the A. D. Blumlein antenna, a slit is cut along the entire length of a half-wave vertical cylindrical tube. To adjust the antenna in agreement with the feeder, a slot width adjustment device is used, which is inconvenient for practical use.

A. Alford slot cylindrical antenna is known, containing a metal pipe with a continuous longitudinal slot, a short circuit at one end of the slot and a device for exciting the antenna at the other end of the slot. The diameter of the pipe is 0.12X...0.15X, where X is the wavelength in free space. In this antenna, the gap is bridged by the outer and inner surfaces of the pipe. The antenna, due to the relatively small diameter of the pipe relative to the wavelength, represents an inductive reactance. Another consequence of gap shunting is an increase in phase velocity relative to the free-space wavelength; the larger the smaller the pipe diameter. Therefore, the slit length is chosen to be equal to several wavelengths in free space.

A cylindrical slot antenna is known for emitting horizontally polarized high-frequency waves, containing a conducting cylinder with a longitudinal slot, short-circuited at both ends of the cylinder, excited by a coaxial cable, the outer conductor of which is galvanically connected to the first edge of the slot, and the central conductor is galvanically connected to the second edge of the slot .

A common disadvantage of these antennas is that they do not have sufficiently simple devices for matching with the feeder. Because of this, the process of tuning the antenna in coordination with the feeder at a given operating frequency becomes more complicated.

The purpose of the work is to develop a cylindrical slot antenna with simple device agreement with the feeder. The antenna length should not exceed one wavelength in free space. The matching device should be convenient when tuning a cylindrical slot antenna by matching to the operating frequency band.

To achieve this goal, numerical and full-scale experiments were carried out.

1. Statement of the problem

There is a known option for exciting a slot antenna using a coaxial cable, wherein the outer conductor of the coaxial cable is galvanically connected to one wide edge of the slot, and the central conductor is galvanically connected to the opposite wide edge of the slot. In the area of the gap, the sheath and outer conductor of the coaxial cable are removed, and the central conductor in the dielectric is laid over the gap. If the diameter of the pipe is relatively large, then matching with the cable with this method of exciting the slot is achieved by choosing the distance I from the excitation point to the narrow edge of the slot. With a relatively small pipe diameter, this method does not achieve the desired goal.

There is another known option for exciting a slot antenna using as a matching device an open section of a coaxial transmission line at the end, which turned out to be effective when the slot is made on a metal strip.

It is required to study the behavior of matching the antenna with the feeder for the mentioned methods of exciting a cylindrical slot antenna, provided that the diameter of the pipe in which the slot is made is much smaller than the wavelength.

2. Methods for solving the problem

2.1. Theoretical method

For a slot antenna on a cylinder of finite length, a numerical experiment was carried out in a rigorous formulation using a direct space-time method for solving Maxwell's equations in integral form. The direct time method solves the boundary value electrodynamic problem generalized to four-dimensional space. The boundary value problem formulated for a continuous continuum is reduced to variational and projection-grid models. This takes into account the actual design of the exciter and matching device. The electrodynamic structure is exposed to a short video pulse, exciting almost all possible types natural oscillations of the object under study, which makes the observed reaction unfolded in time highly informative.

2.2. Experimental method

To conduct experimental studies, three mock-ups of a cylindrical slot antenna were made. Moreover, in all three models the slit length was the same, equal to 0.888 wavelengths in free space.

In the first layout, the antenna is excited by a coaxial cable, the braid of which is galvanically connected to one edge of the slot, and its central conductor is galvanically connected to the other edge of the slot.

In the second layout, the antenna is excited by a coaxial cable, the braid of which is galvanically connected to one edge of the slot, and its central conductor is connected to the central conductor of the matching cable section located on the second edge of the slot. The braid of the matching cable section is galvanically connected to the second edge of the slot.

In the third layout, the antenna is excited by a coaxial cable, the braid of which is galvanically connected to one edge of the slot, and its central conductor is connected to the central conductor of the matching section of the cable, which is laid through a matching cylinder galvanically connected to the second edge of the slot. In this case, the braid of the matching cable section is not galvanically connected to anything.

Measurements of the parameters of a cylindrical slot antenna were carried out in accordance with the diagram shown in Fig. 1, using the OZOR-YUZ complex transmission and reflection coefficient meter according to its operating instructions. Instrument calibration for calibration measures - idle speed“XX”, short circuit “Short circuit”, matched load “Load.” were carried out with the connection of calibration standards to the measuring cable through the transition E2-113/4.

Rice. 1. Scheme for measuring the parameters of a cylindrical slot antenna

Using a meter of complex transmission and reflection coefficients, -SWR, the real and imaginary parts of the complex resistance are measured in the section corresponding to the connection of the measuring cable with the antenna cable, which is designated below as section T2T2.

The measurements were carried out at an antenna site with no reflective objects at a distance of up to 5 m. The slot antenna was installed vertically with the lower part of its cylinder supported on wooden stand, which was attached to the measuring tripod. The installation height of the slot antenna (the lower part of its cylinder) relative to the surface of the test site was at least 1.7 m.

From the theory of a transmission line of finite length (Fig. 2) it is known that the total equivalent resistance

transmission line Zg

in section T2T2,

applied at a distance / from the load with resistance, is determined by the following formula: 2н + iZвtg (р/)

Zв + йнЧ (р/) "

Rice. 2. Finite length transmission line

Here 2b is the characteristic impedance of the transmission line; P - phase coefficient; Zn - load resistance; Zg - internal resistance of the generator; / is the distance from the load to the section in question in the transmission line.

In the experiments, the role of a piece of cable of length / is played by the antenna cable, the role of a piece of cable between sections T2T2 and TT is played by the measuring cable.

When measured according to the diagram in Fig. 2, the complex transmission coefficient meter shows the values of the real and imaginary parts of the antenna input impedance, transformed to the antenna cable input, i.e. 2(/) .

In order to find the resistance directly at the antenna input (without the influence of resistance transformation by the measuring cable), we express it from formula (1), assuming that we know 2 (/).

2 (/)-iZ in^ (p/)

Zв - iZ (/) ^ (р/)■

The measurement results below are recalculated using this formula.

3. Results obtained

3.1. Antenna excitation option with galvanic contact of the central conductor of the coaxial cable with the edge of the slot

To conduct full-scale experiments, the first prototype of a cylindrical slot antenna was made (Fig. 3).

The antenna model 1 contains a housing 2 with a longitudinal slot 3 and a coaxial cable 6. The housing 2 is made of a piece of cylindrical aluminum pipe with a length of 1DA, with an outer diameter of 0D4A, and a wall thickness of 0.0044^. The longitudinal slot 3 with the first 4 and second 5 edges has a length of 0.888^ and a width of 0.033^. The length of coaxial cable 6 RK-50-2-11 is 640 mm, which is half the wavelength in the cable at an operating frequency of 332 MHz.

The outer conductor of the coaxial cable is fixed to the first edge of the slot to form galvanic contact with the antenna body. In the slot area, the sheath and outer conductor of the coaxial cable are removed; the central conductor is galvanically connected to the second edge of the slot.

The cable is fixed on the surface of the cylinder along a straight line, diametrically opposite to the longitudinal axis of the slot, with a bend towards the slot at a point opposite the point of excitation of the slot. The dependences of the real and imaginary parts of the antenna input resistance obtained by recalculating the experimental results using formula (2) are shown in Fig. 4 and 5, respectively.

Rice. 3. Layout of a cylindrical slot antenna

Experimental * Theoretical

Frequency, MHz

Experimente Georetical Youkaya

Frequency. MHz

Rice. 4. Dependence of the real part of the antenna input impedance on frequency: a - in the operating frequency range; b - in a wide frequency range

Rice. 5. Dependence of the imaginary part of the input resistance on frequency: a - in the operating frequency range; b - in a wide frequency range

The dependence of SWR on frequency over a wide range of antenna frequencies is shown in Fig. 6.

Experiment * * Theoretical

300 400 500 600 700 800 900 1000

Frequency, MHz

Rice. 6. Dependence of SWR on frequency over a wide frequency range

From examination of the graphs shown in Fig. 5, it can be seen that the imaginary part of the antenna input resistance in a wide frequency range takes positive values, i.e. it is inductive. Therefore, to compensate for the inductive component of the antenna input impedance, it is necessary to use a capacitive-type matching device. In the second prototype, we will use as a matching device an open-ended segment of a coaxial transmission line with a length of less than a quarter of the wavelength. The input resistance of such a segment is capacitive. As a result, such a matching device compensates for the inductive part of the input impedance of the cylindrical slot antenna.

3.2. Antenna excitation option using a matching cable section

So, in the second version of antenna excitation, a section of a coaxial transmission line open at the end, less than a quarter of the wavelength in length, is used as a matching device (Fig. 7).

As is known, the input impedance of a transmission line segment open at the end with a length of less than a quarter of the wavelength is capacitive. As a result of the sequential inclusion of such a matching device at the operating frequency, the inductive part of the antenna input impedance is compensated.

In the second prototype of a cylindrical slot antenna, a section of coaxial transmission line 7 is used as a matching device, just as the authors used it in a broadband turnstile slot antenna with a circular radiation pattern with horizontal polarization of the radiation field. A matching segment with a length of 0.028X, where X is the wavelength at the middle frequency of the operating frequency range, is placed on the second edge of the slot to form a galvanic contact between the outer conductor of the cable segment and the pipe. The central conductor of the antenna cable is galvanically connected to the central conductor of the matching cable section. The antenna cable length is 640 mm.

As in the first layout, the cable is fixed on the surface of the cylinder along a straight line, diametrically opposite to the longitudinal axis of the slit, with a bend towards the slit in the vicinity of the slit excitation point.

The graph of the dependence of the real part of the input resistance on frequency (Fig. 8) shows that in the frequency range 330-450 MHz, the value of the real part is equal to (50 ± 10) Ohms. The imaginary part of the input resistance in this range increases from -50 to +120 Ohm; at a frequency of 332 MHz, the value of the imaginary part of the input resistance is zero (Fig. 9). In Fig. Figure 10 shows the dependence of SWR on frequency over a wide range of antenna frequencies.

Rice. 7. Cylindrical slot antenna

Experiment Theoretical

" G " 1 " -1- i

Experiment Theoretical

1 ■ ■ ■ -,- -

Frequency. MHz

Frequency, MHz

Rice. 8. Dependence of the real part of the antenna input impedance on frequency: a - in the operating frequency range; b - in a wide frequency range

Okciicj "Gsors HIMCHT and chesk

Experiment Theoretical

Frequency, MHz

Rice. 9. Dependence of the imaginary part of the antenna input resistance on frequency: a - in the operating frequency range; b - in a wide frequency range

Experiment * Theoretical

■ ■ 1 1 ■ « ■ ■

Frequency. MHz

Rice. 10. Dependence of SWR on frequency in the operating frequency range

The results of a study using a numerical method of the dependence of the resonant frequency of the antenna on the length of the matching cable section are shown in Fig. 11.

At the resonant frequency, the imaginary part of the antenna input impedance is zero, and the SWR takes on a minimum value. As follows from examining the graphs in Fig. 11, as the length of the matching cable section increases, the SWR minimum shifts to the low frequency region. When the length of the matching cable section changes by 3 mm, the resonant frequency shifts by 3.5 MHz, i.e., when the length of the matching cable section changes by 1 mm, the point shifts

resonance frequency is approximately 1.2 MHz. Therefore, when fine-tuning the antenna to the operating frequency, it is necessary to change the length of the matching cable section by fractions of a millimeter. The need to select the length of the matching cable segment with an accuracy of fractions of a millimeter complicates the process of tuning the antenna.

Ek "-Te spsriment heretical

Frequency, MHz

Rice. 11. Dependence of the antenna SWR on frequency at different lengths of the matching segment:

a - 12 mm; b - 15 mm; c - 18 mm; g - 21 mm

3.3. Antenna excitation option using a matching cable section and a matching cylinder

In order to perform a more convenient adjustment of the antenna by agreement, an additional device was introduced into the antenna in the form of a short tubular cylinder, hereinafter called a matching cylinder (Fig. 12, 13). A matching cylinder with a length of 0.011^ and a diameter of 0.0044^ is located on the pipe in the vicinity of the second edge to form galvanic contact with the pipe. The matching cable section is laid inside the matching cylinder. The central conductor of the antenna cable is galvanically connected to the central conductor of the matching cable section. In Fig. 12 this connection is conventionally shown in the form of a mechanical connection by twisting the central conductors. In a real layout, the matching cable section is a natural continuation of the exciting cable, on which the sheath and outer conductor have been removed in the slot area. To ensure a larger area of galvanic contact with the pipe, the cable is attached to the pipe using couplings with a cylindrical hole and a cylindrical surface adjacent to the pipe.

The idea of including a matching cylinder in the matching device is as follows. The inner surface of the matching cylinder and the outer surface of the outer conductor of the matching cable section form a cylindrical capacitor. (Between the plates of this capacitor is the dielectric shell of the coaxial cable). This additionally formed capacitor is connected in series with the capacitor formed by the matching cable section. As is known, two capacitors connected in series together have a capacitance that is smaller than the smaller capacitance of the connected capacitors.

ditch The length of the matching cylinder should be chosen so that the resulting capacitor has a capacitance close to the required capacitance for matching. Then, tuning the antenna by agreement can be done by changing the capacitance of a large size. That is, as a matching cable section, you can select a relatively long cable section, and adjust it by cutting it. It turns out that the cut parts of the cable will have a relatively large length. This circumstance makes tuning the antenna more convenient.

Rice. 12. Model of a cylindrical slot antenna with a matching cylinder and a matching section of cable: 1 - pipe; 2 - matching cable section; 3 - matching cylinder;

4 - slot; 5 - feeder

Rice. 13. Section А-А matching device in Fig. 12: 1 - matching cylinder; 2 - cable sheath; 3 - outer conductor of coaxial cable; 4 - dielectric; 5 - central conductor of the coaxial cable; 6 - pipe wall

Length of the matching segment 32 mm - "- Experiment - Theoretical Length of the matching segment 28 mm - Experiment "- Theoretical Length of the matching segment 26 mm --- Experiment - Theoretical

\ V Y\ V\ y\ V\ \\ u V V and \\ v

\\ V \\ \ \ \ \\ v k\ V 1 \ L \

\\ \ u \ v y- \ \v \v yU J?" X/ A V J /U // (/ / / // y

300 310 320 330 340 350 360

Frequency, MHz

Rice. 14. Dependence of antenna SWR on frequency at different lengths of the matching segment

In Fig. Figure 14 shows the calculated dependences of SWR on frequency for various values of the length of the matching segment with a constant length and diameter of the matching cylinder.

The electrodynamic model of the antenna takes into account all structural elements including couplings. As the length of the matching segment increases, the minimum SWR shifts to the low frequency region. When the length of the matching segment changes by 4 mm, the resonant frequency shifts by 2 MHz, i.e., when the length of the matching segment changes by 1 mm, the resonant frequency shifts by 0.5 MHz. Thus, with the introduction of a matching cylinder into the antenna design, tuning the antenna to a given frequency turns out to be more convenient.

4. Discussion of results

So, we have considered a slotted cylindrical antenna made on a metal pipe with a diameter much smaller than the wavelength. The pipe has a length greater than the wavelength, and the length of the slit has a length less than one wavelength in free space, so the slit is shorted

from both ends.

The input impedance of such an antenna, when excited at the center by a coaxial cable in such a way that its outer conductor has galvanic contact with one edge of the slot, and the central conductor has galvanic contact with the other edge of the slot, has a large inductive component. As a result, the antenna is poorly matched with the feeder. By shifting the excitation point along the wide edge of the slot, it is not possible to match the antenna with the feeder.

By sequentially connecting a short matching section of cable, it is possible to compensate for the reactive (inductive) component of the antenna input impedance at one frequency and thus achieve ideal matching at one operating frequency. However, this reveals greater criticality to the length of the matching cable section.

The introduction of a matching cylinder into the design makes it more convenient to tune the antenna to the operating frequency. This convenience lies in the fact that in order to shift the resonant frequency by a certain amount, it is necessary to change the length of the matching cable by a larger amount compared to the amount that is required in its absence.

The proposed method and device make it possible to conveniently match an antenna with a feeder, in which the pipe diameter is much less than the wavelength, and the slot length is less than the wavelength.

As follows from examining the graphs in Fig. 8-10, 14 in the range of antenna operating frequencies (330...334 MHz) there is a good quantitative agreement between the calculated and experimental results. The calculated and experimental dependences on the frequency of the real and imaginary parts of the input resistance and SWR coincide with each other with graphical accuracy. Outside the operating range (at f< 328 МГц и при f >332 MHz) there is a noticeable difference in the calculated and experimental results. This difference can be explained by the fact that the antenna cable in experiments manifests itself as a pass-through resonator formed by a section of the transmission line, commensurate with the wavelength, loaded at one end onto the input impedance of the antenna, and at the other end - onto the resistance formed by the inhomogeneity in the form of a transition from one type of cable to another type of cable via radio frequency connectors. The mentioned heterogeneity is formed as a result of the fact that each of the cables has a characteristic impedance that differs from 50 Ohms by a certain amount. In addition, RF connectors are not perfectly matched. An additional error is introduced into the measurement results because when calibrating the “0bzor-103” device, an additional transition is used from the RTS connector to the “Expertise” connector. The resonant properties of a pass-through resonator appear in the form of an oscillating component on graphs of the dependence of the real and imaginary parts of the antenna input impedance on frequency. In the vicinity of the operating frequency, at which ideal matching can be achieved, the influence of the pass-through resonator is eliminated.

Conclusion

Thus, theoretical and experimental studies have been carried out on three versions of a cylindrical slot antenna with three options of excitation devices:

With a known excitation device (without the use of matching devices);

With an excitation device using devices for matching the antenna with the feeder in the form of a short piece of cable open at the end;

With an excitation device using an original matching device, which includes a matching section of coaxial cable and a matching cylinder.

Moreover, in all three options, the pipe diameter is much smaller than the wavelength, and the antenna length does not exceed one wavelength in free space. Original device matching provides simple and convenient matching and tuning of a cylindrical slot antenna to the operating frequency. Theoretical and experimental results in the operating frequency range are in good quantitative agreement.

The work was carried out with the financial support of the Ministry of Education and Science of the Russian Federation within the framework of the complex project “Creation of high-tech production of antennas and hardware modules for a dual-frequency radio beacon complex for a meter-band landing system in the ILSIII format of ICAO category for civil aviation airfields, including airfields with high levels of snow cover and difficult terrain. locality" under agreement No. 02.G25.31.0046 between the Ministry of Education and Science of the Russian Federation and the Open Joint-Stock Company "Chelyabinsk Radio Plant "Polyot" in cooperation with the lead contractor of R&D - the Federal State Budgetary educational institution higher professional education "South Ural State University" (national research university).

Literature/References

1. British patent No. 515684. HF Electrical Conductors.

2. Voytovich N.I., Klygach D.S., Repin N.N. Slot Turnstile Antenna. 7th European Conference on Antennas and Propagation (EuCAP - 2013), 8-12 April 2013, Gothenburg, Sweden, 2013, p. 1208-1212.

3. Alford A. Long Slot Antennas. Proc. of the National Electronics Conference, Chicago, IL October 3-5, 1946, p.143.

4. Kraus J.D. Antennas - 1988, TATA McGRAW-HILL Edition, New Delhi, 1997. 894 p.

5. Voytovich N.I., Klygach D.S., Repin N.N. Slot Turnstyle Antenna. 2013 7th European Conference on Antennas and Propagation (EuCAP), IEEE Xplore, pp. 1209-1212.

6. Weiland T. A Discretization Method for the Solution of Maxwell's Equations For Six-Component Fields. Electronics and Communication, (AEU), 1977, vol. 31, pp. 116-120.

7. Pimenov A.D. Technical electrodynamics. M.: Radio and communication, 2005. 483 p.

Klygach Denis Sergeevich, Ph.D. tech. Sciences, South Ural State University, Chelyabinsk; [email protected].

Dumchev Vladimir Anatolyevich, engineer, South Ural State University, Chelyabinsk; [email protected].

Repin Nikolay Nikolaevich, engineer, South Ural State University, Chelyabinsk; [email protected].

Voitovich Nikolai Ivanovich, Doctor of Engineering. Sciences, South Ural State University, Chelyabinsk; [email protected].

DOI: 10.14529/ctcr150203

A SLOTTED CYLINDER ANTENNA

D.S. Klygach, South Ural State University, Chelyabinsk, Russian Federation, [email protected], V.A. Dumchev, South Ural State University, Chelyabinsk, Russian Federation, vladimir. [email protected],

N.N. Repin, South Ural State University, Chelyabinsk, Russian Federation, [email protected],

N.I. Voytovich, South Ural State University, Chelyabinsk, Russian Federation, [email protected]

A slotted cylinder antenna with the original matching device is presented in the paper. A slotted cylinder antenna is made on the shape of longitudinal slot based on a metallic tube with diameter much smaller than the wave length. The length of the slot is much smaller than the wave length in

free space. The antenna parameters are found by numerical method in the strict electrodynamic formulation of the problem. For this purpose the construction of the matching device is taken into account in the electrodynamic model of the antenna. Reached theoretical results in antenna bandwidth of examined antenna demonstrate good quantitative match with experimental results. The method and original matching device suggested in the paper are characterized by simplicity of the antenna matching with a feeder.

Keywords: slot antenna, pattern, bandwidth, VSWR.

BIBLIOGRAPHICAL DESCRIPTION OF THE ARTICLE

REFERENCE TO ARTICLE

Cylindrical slot antenna / D.S. Kligach,

B.A. Dumchev, N.N. Repin, N.I. Voitovich // Bulletin of SUSU. Series “Computer technologies, control, radio electronics”. - 2015. - T. 15, No. 2. -

pp. 21-31. DOI: 10.14529/ctcr150203

Klygach D.S., Dumchev V.A., Repin N.N., Voytovich N.I. A Slotted Cylinder Antenna. Bulletin of the South Ural State University. Ser. Computer Technologies, Automatic Control, Radio Electronics, 2015, vol. 15, no. 2, pp. 21-31. (in Russ.) DOI: 10.14529/ctcr150203

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