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In this paper, we developed an analytical model that makes it possible to estimate the response (i.e., the voltage or current at the output) of a dipole antenna to arbitrary-shaped electromagnetic pulse if the minimum information about the antenna is available (it is enough to know the following parameters of the antenna: working frequency range, gain, and wave impedance of the radiofrequency port). The developed model is validated by comparing the computed responses of VHF- and UHF-band dipole antennas to wideband electromagnetic pulses with the measurement results published in the literature. The validation demonstrates that the model estimates the values of the most important antenna-response parameters (total energy, amplitude, and voltage rate), which define the requirements to the radio-equipment terminal protection devices, with reasonable accuracy. The possibilities of increasing the response estimation accuracy by numerical modeling of the antenna are investigated (MoM and FDTD methods are involved).

Numerical simulation results for multimodule antenna array in form of linear array consisting of rectangular subarrays (modules) are given. It's shown that grating lobes appear in the array factor if the amplitude distribution within a module and within a system of modules are independent from each other. The dependence of grating lobes level on amplitude distribution parameters is considered.

The work deals with numerical modeling results of two wire antennas that have quasi-isotropic radiation patterns in one of the main planes. First antenna is a modified Franklin antenna, which provides wider frequency bandwidth according to feed matching criteria. This antenna have isotropic radiation pattern in H-plane. It is series-fed antenna array. Second antenna is a modification of loop antennas with loops perimeter equal to one and two wavelengths. The loops in this antenna are bowed on some angle. It forms quasi-isotropic radiation pattern in bowed plane. In H-plane the antenna is a linear series-fed antenna array. The antennas were modeled using method of moment. The dimensions of antennas were optimized using crite-rias of matching and reaching of omnidirectional radiation pattern in horizontal plane.

The array antenna consisting of rectangle form subarrays (modules) is considered. Modules are placed in space in two ways: on the plane and on the lateral surface of a cylinder, forming a multi-faceted array antenna. The effect of number of array’s defective radiating elements (individual radiators or modules) on antenna pattern parameters and antenna directivity is investigated. Three forms of flat array’s aperture are considered: rectangle, elliptical and octagonal. The numerical simulation is used for analysis. Defective radiating element is referred to as that one, which has zero excitation amplitude. Defective elements are placed on the antenna’s surface randomly.

The influence of interchannel and intrachannel non-identities on digital antenna array characteristics is studied. Non-identities are random amplitude and phase excitation errors of receive/transmit modules. Cases of fast and slow fluctuations of random errors are considered. Variation frequency of fast fluctuations is much greater than scanning frequency. Variation frequency of slow fluctuations is much less than frequency of scanning.