Faculty of Computer Information Technologies and Automation (CITA)

Introduction

The creation of a radio engineering object at the design stage involves minimizing its visibility, but in some cases additional external masking is required. When When designing this kind of object, developers determine the level or class of the object's invisibility. ... Especially when it comes to military equipment and such objects as: buildings, ships, radar stations, etc. To achieve the desired results, it took centuries of development of such a direction as camouflage. AT In this work, camouflage takes on a new round of development. Radio engineering systems that include antenna complexes require special protection against detection by other location complexes and systems. So the disguise such objects are currently developing rapidly and everything more states provide diverse, new technologies called «Stealth».

To achieve high performance effect in disguise takes into account the inferiority of human perception organs. The same way there is a process of hiding objects from radio technical radars devices. Nowadays, disguise has acquired the status of a military craft, which requires special highly qualified preparation. 

1. Theme urgency

More and more these days complexes are equipped with various electronic devices that able to detect objects of various sizes and target orientation. Almost any object has metal elements on its surface that serve as a frame or its structural part. Any metallized surfaces reflect radio waves, that is, they act as a passive transmitting antenna, the presence of a large number of metal devices and structures on the surface leads to an increase in the visibility of this object. This leads to the fact that during reconnaissance operations probability finding this object increases significantly, which is an extremely negative phenomenon.

Master's The work is devoted to an urgent scientific task of studying ways to mask strategic objects that have in his the composition of both antenna systems and complexes, and their absence. In the course of work, it is planned to improve the existing method of reducing the reflected signal, and at the same time the general visibility of the object [1].

2. Goal and tasks of the research

The purpose research is the development of a device based on a new material to reduce the level of the reflected signal of strategic objects, which has composed of important hardware and components.

The main objectives of the study:

1. Research on existing methods of radio camouflage and the transition from general to specific.
2. Examine properties radio-absorbing and radio-transparent materials
3. Conduct a comparative analysis and choose the appropriate
4. Simulate a device in software product
5. Calculate parameters based on simulation results

Object of study: Strategic object, covered with absorbent material.

Research subject : reduction of reflected radiation due to absorption of electromagnetic energy and its transfer to another state.

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

In the work of Leonid Ustimenko, an ultra-wide-range radio-absorbing material was developed based on a nanostructured ferromagnetic microwire (NFMP) in glass insulation. The main radio-absorbing element in it is NFMP, which is a thin metal core in glass insulation. Due to the difference in the coefficient of thermal expansion of metal and glass, as well as the presence of a nanostructured transition layer, the material of the metal core is under the influence of gigantic stresses and has unique electrophysical characteristics in the microwave range. The current work involves the improvement of this approach [4]. To improve the existing device, it is necessary to use several NFMP layers with different integration steps, which will expand the range of absorbed frequencies. Also, the back side of the material must be covered with hard magnetic rubber for better adhesion to the metallized surface. This material can be used to cover directly the protected object or, to obtain a greater effect, cover the spherical frame, which will reduce the ESR of the protected object. [1]. Device has no analogues, therefore this system is an innovation.

Make objects invisible for objects of particular importance, it is extremely difficult, since passive and active antenna systems can be located on these objects. maybe only slightly reduce the possibility of their detection by intelligence RES, if covered with materials that absorb EME energy and apply oil-reflecting forms.

A decrease in RLR can be achieved in several ways: 

- through elimination corner reflection phenomena and magnification energy re-emitted in other directions. It is implemented through selection of a special aircraft form. A demonstration of this technique is aircraft F-117A. 

- using special radio absorbing cover. 

- by increasing the share energy re-emitted into space by multiple and combined harmonics of the probing signal and a corresponding decrease in the share of energy emitted by the main harmonics. This technique, based on the inclusion in the reflective the surface of nonlinear (for example, semiconductor) sections is expensive and technically complex, and therefore not yet found wide application [7]. 

An emitter with a large power, can determine not only the presence of an object in space, but also its geometric shape. Consequently, the RCS directly depends on the size of the object. So than the larger the object, the higher the likelihood of being seen. The disadvantage of radio engineering objects, which include antenna system, is a large RCS.

Such goals have a difficult configuration and consist of many different reflectors. Flat parts of objects reflect all the energy, which leads to specular, or diffuse display; the raised areas look like «shiny» points. The latter include a simple the form – ball (sphere) that has a minimum reflective surface.

AT effective scattering surface   by Skolkin – it is a quantitative measure the ratio of the power density of the signal scattered in the direction receiver,  к  power density radar wave incident on the target, taking into account their vector properties [9].

E₀ ‒ electrical component incident electromagnetic field;

E_s ‒ magnitude electric component of the scattered electromagnetic field, measured hypothetical observer;

R ‒ distance from target to hypothetical observer.

For decline visibility, various methods of disguise are used. AT particular antennas and complexes are covered with various materials or embedded in itself antenna structures that reduce the RCS of the complex. EPR is conditional size to express a quantitative assessment reflective properties any radar goals and is calculated according to the formula:

P₂ — power secondary radiation (flux of energy of an electromagnetic wave, scattered when falling on target);    

П₁ — flux density energy coming from source of radiation;

D — coefficient directional reflective object [7, 10].

In the work of Leonid Ustimenko, an ultra-wide-range radio-absorbing material was developed based on a nanostructured ferromagnetic microwire (NFMP) in glass insulation. The main radio-absorbing element in it is NFMP, which is a thin metal core in glass insulation. [4 link to article]. Due to the difference in the coefficient of thermal expansion of metal and glass, as well as the presence of a nanostructured transition layer, the material of the metal core is under the influence of gigantic stresses and has unique electrophysical characteristics in the microwave range.   The disadvantage of this method is a high level of EME reflection. [11]. 

The proposed method for reducing reflections of radio engineering objects will have a structure as in Figure 3:

Conclusion

AT currently at the Department of Radio Engineering and Information Security work on elimination of this drawback by modeling the object in software CST product Studio. Model compiled in the same software product, which confirms the usefulness devices by reducing the reflection of the EME antenna described in the patent of Leonid Ustimenko [1].

When writing this abstract the master's work has not been completed yet. Final completion: April 2021 year. The full text of the work and materials on the topic can be obtained from the author or his manager after the specified date.

References

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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.