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Abstract

Сontent

Introduction

Create a low-profile radio engineering object from the time of design is easier than trying to hide an existing one. When designing such an object, developers initially plan its visibility / invisibility. Especially if it concerns objects such as ships, buildings, radar stations, etc. To achieve the greatest possible visibility for centuries, a trend has developed such as camouflage. In this work, disguise acquires a new stage of development. Radio engineering objects, which include antenna systems, especially require protection from detection by other location stations. Thus, the disguise of such types of objects is currently developing rapidly and more and more states are providing new technologies of "invisible."

To achieve maximum effect in disguise, the imperfection of a person, his body, is taken into account, if it concerns visual masking. Similarly, the process of masking objects from the radar of radio engineering devices is under way. At one time, disguise gained the status of a military direction, which requires special training. 

1. Theme urgency

In the modern world, more and more complexes are equipped with radio-electronic devices that facilitate detection of various kinds of objects. Since any object itself reflects radio waves, that is, it has its effective scattering surface (RCS), the presence of additional metal devices and structures leads to an increase in the visibility of this object. This leads to the fact that when conducting reconnaissance operations the probability of finding this object is significantly increased, which is an extremely negative fact.

The master's work is devoted to the actual scientific problem of research into the method of reducing the effective scattering surface of radio engineering objects that have antenna systems in their composition. In the course of the work, it is planned to improve the existing method of reducing RCS [1].

2. Goal and tasks of the research

Development of an apparatus for reducing the effective surface of the scattering of radio engineering objects, which includes antenna systems, is the goal of research.

Main tasks of the research:

  1. Examination of existing methods of radio masking.
  2. Study the properties of radio-absorbing and radio-transparent materials
  3. Carry out a comparative analysis and choose the right one
  4. Model the device in the software product
  5. Calculate the parameters based on the simulation results

Research object: antenna system, that is placed under the fairing.

Research subject: reduction of the effective dispersion surface due to the fairing.

3. An approach to the ways of reduction the radar cross–section

In Donetsk National Technical University work in this direction was conducted by Demidov Oleg Aleksandrovich at the Department of Radio Engineering and Technical Information Protection under the leadership of Paslyon Vladimir Vladimirovich [1]. In the course of the work, a device has been developed to reduce the effective scattering surface. The essence of it is that around the antenna creates a radio-opaque environment – a pair of mercury. The device has no analogues, therefore this system is an innovation.

The device contains a radio-transparent cap 1 which is sealed in front of the radiating opening of the antenna 2 on the basis of 3. As can be seen, under the base 3, from the outside of the cap 1 is a device 4 for pumping and pumping out the working medium. It contains a chamber 5 with a gaseous mixture 6 and a block 7 for controlling the parameters of the working medium under the hood.

The device for RCS-reduction

Figure 1 – The device for RCS-reduction

It is extremely difficult to make objects unobtrusive for RCS. It is possible to only slightly reduce the possibility of their detection by reconnaissance RCS, if covered with materials absorbing the energy of the EMW, or to use non-reflective forms. However, a noticeable result in reducing the radiovisibility can be achieved only in the case of a sharp decrease in the EPR of the objects. Thus, a reduction of the RCS by a factor of 16 reduces the range of radar detection of the object by a factor of 2 and more [6]

Reducing RLV can be achieved in several ways: 

- by eliminating the phenomena of angular reflections and increasing the energy re-emitted in other directions. He realizes by choosing a special form of aircraft. The demonstration of this method is the F-117A aircraft. 

- when using a special radio-absorbing coating. 

- due to an increase in the fraction of energy reradiated in space at multiple and combined harmonics radiated to the fundamental harmonics. This approach, based on the inclusion of non-linear (eg semiconductor) sites in the reflecting surface, is expensive and complex in technical terms, and so far has not found wide application [7].

The emitter, which has a high power, can determine not only the presence of an object in space, but also its geometric shape. Consequently, EPR directly depends on the size of the object. So, the larger the object, the higher the probability of being noticed. The disadvantage of radio engineering objects, which have antenna systems in their composition, is a large RCS. Some indicators are given below in Table 1 [8].


Table 1 – Mean values of RCS
Radiolocation target RCS, м^2
Jet fighter 3-5
Transport aircraft до 50
Transport of small tonnage 150
Transport of medium tonnage 7 500
Transport of large tonnage 15 000
Cruiser 14 000
Boat 100
Human 0,8 - 1

Such targets have a complex configuration and consist of many different reflectors. Flat parts of objects reflect all energy, which leads to a mirror or diffuse mapping; The convex sections look like "shiny" points. The latter includes a simple form - a sphere, which has a minimal reflecting surface.

In its definition by Skolkin, the radar cross-section (RCS) is a quantitative measure of the ratio of the signal power density scattered in the direction of the receiver to the power density of the radar wave incident on the target, taking into account their vector properties [9].

E0 ‒ the magnitude of the electrical component of the incident electromagnetic field;

Es ‒ the magnitude of the electrical component of the scattered electromagnetic field, measured by a hypothetical observer;

R ‒  distance from the target to the hypothetical observer.

To reduce the visibility of various methods of disguise. In particular, the antennas and complexes are covered with various materials or embedded in the antenna itself, structures that reduce the RCS of the complex. RCS is a conditional value for the expression of a quantitative estimate of the reflective properties of any radar target and is calculated by the formula

σ t=P2/П1*D   ,

P2 — the power of the secondary radiation (the energy flux of the electromagnetic wave scattered when it falls on the target);

П1 — the density of the energy flow from the source of irradiation;

D — the directivity coefficient of the reflecting object [7, 10].

The device developed by Demidov and Paslyon to reduce the RCS of the antenna, filling the spherical cap with a gaseous substance, for example, with mercury vapor. During the working phase of the antenna, the gaseous substance is pumped into the reserve capacity, after completion of the work, the space is again filled with vapors of this gaseous substance. The disadvantage of this method is the direct action of vapors of gaseous matter on the elements of the antenna system, which can lead to a change in its characteristics [11].

The proposed method for reducing the RCS of radio engineering objects will have a structure, as in Figure 2:

The device for RCS-reduction

Figure 2 – The device for RCS-reduction
(animation: 3 frames, 10 cycles of repeating, 132 kilobytes)

Conclusion


Currently, the work of the modeling on this object is on the Department of Radio Engineering and Information Protection in the software product CST Studio. A model is built in the same software product, which confirms the usefulness of the device to reduce the RCS antenna, described in the Demidov and Paslyon patent [1].


Further studies focused on the following aspects:

  1. Пристрій для зменшення ефективної поверхні розсіювання антен : патент на корисну модель №91502 (UA).  / Демідов О. О. (UA), Пасльон В. В. (UA) ; заяв. 13.01.2014 ; опубл. 10.07.2014, Бюл. №13. 3 с.  
  2. Голин Г. М., Филонович С. Р. Классики физической науки (с древнейших времен до начала XX в.) : Справ. пособие. – М. : Высш. шк., 1989. – 576 с. 
  3. Уфимцев П. Я. Теория дифракционных краевых волн в электродинамике. Введение в физическую теорию дифракции / П. Я. Уфимцев; пер. с англ.  – 2-е изд., испр. и доп.  – М. : БИНОМ. Лаборатория знаний, 2012. –372 с.
  4. Ермолов П. П., Пустовойтенко В. В. Севастопольский полигон для измерений радиолокационных, тепловых и лазерных характеристик надводных кораблей (1979—1991 гг.) – 2009 19th Int. Crimean Conference “Microwave & Telecommunication Technology” (CriMiCo’2009). 14–18 September 2009.
  5. Алексеев А. Г., Штагер Е. А., Козырев С. В. Физические основы технологии Stealth. – СПб. : ВВМ, 2007. – 283 с.
  6. Палий А. И. Радиоэлектронная борьба. – 2-е изд., перераб. и доп. – М. : Воениздат, 1989. – 350 с.
  7. Степанов Ю. Г. Противорадиолокационная маскировка. / Степанов Ю. Г. изд. «Советское радио», Москва – 1968, 144 с.
  8. Канащенков А. И., Меркулов В. И., Самарин О. Ф. Облик перспективных бортовых радиолокационных систем. Возможности и ограничения. – Москва: ИПРЖР, 2002. – 176 с. 
  9. Сколник М. И. Справочник по радиолокации. / Пер. с. англ. Под общей ред. Трофимова К. Н. В четырех томах. М. : Сов. Радио. – 1976–1978 гг.
  10. Рябченко В. Ю., Паслён В. В, Исследование способов уменьшения эффективной поверхности рассеивания радиотехнических объектов – 2017 13-я Международная молодёжная научно-техническая конференция «Современные проблемы радиоэлектроники и телекоммуникации, РТ-2017», г. Севастополь, РФ, 21-25 ноября 2017.
  11. Рябченко В. Ю., Паслён В. В, Обзор способов уменьшения эффективной поверхности рассеивания радиотехнических объектов. Конференция  “Донбасс будущего глазами молодых ученых” , – Донецк, СМУ, ДонНТУ, 21 ноября 2017.