R.Yu. Borodulin - Ph.D.(Eng.), Doctoral of Department of Radio Communication, Military Telecommunication Academy named after the Soviet Union Marshal S.M. Budienny (St. Petersburg) E-mail: borodulroman@yandex.ru O.Yu. Perfilov - Dr.Sc. (Eng.), Deputy Director, JSC «VNII «Etalon» (Moscow) E-mail: perfilov@bk.ru

The paper presents a technique for the energy evaluation of broadband plate-type antennas obtained by constructive synthesis. It is proposed to use the spectral components of the relative bandwidth of the antenna operating frequencies to obtain a certain «funda-mental» frequency, indicating the equivalent of parallel resonance. Based on the value of the obtained frequency and the relative width of the operating frequencies to it, it is proposed to find the equivalent wave impedance of a broadband antenna, which makes it possible to obtain the maximum possible bandwidth of operating frequencies. It is also possible to obtain other parameters that allow us to evaluate the efficiency of broadband antennas. The article considers a variant of increasing the efficiency of the antenna due to the use of constructive synthesis. Synthesis is performed without changing the overall height of the antenna web. In this case, the elements of the virtual «compensator» of the input resistance are actually synthesized. The process of obtaining the objective function, based on the parameter of the effective length, is presented. The role of the received reactive «compensators» on the broadband of the radiator is shown. Examples of the energy estimation of the initial and several synthesized antennas are given. This shows the process of redistribution of the active power of the generator from other sections of the antenna to its input area corresponding to the component of the antenna activity factor introduced in the article, which is understood as the energy gain due to better selection of the generator power. Alternative versions of synthesized antennas with higher height and width of the radiating surface are presented, broadband properties of which are also explained using the developed estimation technique. The article presents numerical values of the average values of the reflection coefficient in the frequency band of all the antennas under consideration. This indicates the receipt of a significant energy gain for some options. Constructive synthesis makes it possible to improve the energy characteristics of even ideal antennas only by increasing the efficiency of the radiation surface current distributions. This new direction in the synthesis of antennas, its development continues. Of great interest is the use of constructive synthesis to antennas in media with losses. The presented technique can be used not only for plate-type antennas, but also for any other small broadband antennas of arbitrary topology.

 

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