Diffraction effects in the cylindrical monopole and dielectric disk antennas

Abstract

Based on experimental studies and simulation modeling , the influence of diffraction effects on the radiation characteristics of cylindrical monopole antennas and dielectric disk antennas is determined under conditions when the electrodynamic parameters of antenna components are changed. In particular it is established that the oscillating dependence of the angle of maximum radiation and the resonant frequency of monopole cylindrical antennas with the monopole height d_r1 = λ/4 as function of the ground plane radius are explained by different spatial structure of electromagnetic field in the inductive region of antenna with the ground plane radius being multiple of λ/2 and the odd number of times λ/4 (λ-is the wavelength in free space). It is shown that the spatial distributions of electromagnetic fields as the “spatial wave grating” are formed in the inductive region of antennas under test.