Sidenʹ S. Out-of-band characteristics of microwave radiators and development of a wideband planar antennas

The object of research is the electromagnetic processes occurring when radiated by antennas in a wide frequency band. The subject of research is the frequency and directional characteristics of antennas in a wide frequency band. The dissertation work uses the mathematical apparatus of electrodynamics, methods of the theory of antennas and microwave devices, low-frequency methods of computational electrodynamics (method of moments), as well as methods of experimental research of frequency and directional characteristics of antennas in full-scale conditions. For the first time, the frequency dependences of the main electrodynamic characteristics of common types of antennas in a wide frequency band were obtained, which make it possible to correctly take into account the numerical values of the out-of-band gain level in the problems of analyzing the electromagnetic environment; For the first time, a mathematical model was proposed for analyzing the out-of-band level of antenna gain, which differs from the existing ones in that it allows analysis of its value in a specific sector of angles. The method for calculating the antenna gain outside the operating frequency band has been further developed, taking into account the frequency dependence of the reflection coefficient at the antenna input ; For the first time, a number of original topologies of broadband small-sized antennas are presented, a feature of which is their peripheral excitation, does not violate the planarity of the structure. On the basis of computer modeling and experimental research, the possibility of their practical use has been proven.