Катрич В. А., Лященко В. А., Белогуров Є. Ю., Кийко В. І., Пшенична С. В. Харківський національний університет ім. В. Н. Каразіна пл. Свободи 4, м. Харків, 61077, Україна Тел.: 38 (057) 7075548; e-mail: Eugene.Y.Belogurov@univer.kharkov.ua

Katrich V. A., Lyaschenko V. A., Belogurov E. Y., Kyiko V. I., Pshenichnya S. V.

V. N. Karazin Kharkov National University

4      Svoboda Sq., Kharkov – 61077, Ukraine phone: 38 (057) 7075585

Abstract – The results of performance examination by magneto motive forces method are presented for longitudinal slots with changing width cut in wide wall of the rectangular waveguide.

I.  Introduction

Application of longitudinal slots with changing width is considered to be a perspective technique of excitation in the aperture of slotted radiator cut in walls of the waveguide structures amplitude and phase distribution which realizes optimal integral radiation characteristics, i.e. radiation far-field pattern and gain. The absence of publications on these radiators restricts their analysis and practical application.

II.  Main part

The longitudinal slot having the length equaled to / and linearly changing width cl is cut in the wide wall of the rectangular waveguide with a cross-section axb. The waveguide and free half-space were loaded by dielectrics with permittivities s" and correspondingly.

Unknown field E in the antenna aperture is approximated by a set of eigen-functions with complex amplitudes Vp. Because of axial symmetry and due to relationships cl < / and d <X we supposed that only vertical component of the electric field is excited in slots. Particular conductivities YM are equal to the

sum of the external and internal conductivities!’ =Y“ +Y"

pq                     pq                       pq

and are defined by the integrals over slot surface.

The magneto motive force F is calculated for a slot in a sin- gle-mode waveguide. The results of computation of the reflection |sj and radiation |ST |~ coefficients are shown on Fig. 1.

Solid lines are theoretical dependences, whereas dots and crosses show experimental data. As can be seen there is a good correspondence between theoretical and experimental results in spite of approximate character of formulae used.

Fig. 2 illustrates ^I’and |sj dependencies on Rvalue.

Upper indexes indices (1) and (2) of capital letters in Fig. 2 indicate excitation from side dj and d2, correspondingly. It can be seen that radiation coefficient is proportional to d2 , whereas the reflection coefficient displays the inverse proportionality.

Wavelength dependencies of and|sj for ch = 1mm and d2 = 11 mm are shown in Fig. 3. It turned out that the slot with changing width maintains the more than 0.9 and the level

of |s |" less than 0,01 within 30% wavelength band.

Radiation far-field patterns of rectangular and linearly expanding slots are shown in Fig. 4. It can be seen that slots shape strongly effect the shape of slot far-field radiation pattern.

III.  Conclusion

The investigations showed optimization possibility of electrodynamics characteristics for antennas on the basis of long longitudinal slots with changed width cut in the wide wall of the rectangular waveguide.

Джерело: Матеріали Міжнародної Кримської конференції «СВЧ-техніка і телекомунікаційні технології»