Оценка влияния формы простого микрополоскового излучателя на его широкополосность

Abstract

Microstrip antennas are one of the most common types of antennas for mobile objects. Compactness, lightness and conformity make their use convenient and in fact the only solution for the rapidly developing industry of wire-less telecommunications. The key disadvantage of such antennas is their narrow bandwidth inherent in all resona-tor type antennas, microstrip antennas being a particular case. Basically, the narrowband nature of such antennas is due to a pronounced frequency dependence of the input impedance, as a result of which a satisfactory quality of natural matching can be achieved in a frequency band measured in units of percent. The paper considers mi-crostrip radiators of simple geometry: rectangular, square, rhombic, triangular, round, elliptical, located on a sub-strate of fixed geometry with the same dielectric. For each shape of the strip geometry, numerical optimization of the strip dimensions and the position of the excitation point is performed in order to obtain the maximum bandwidth of natural matching in VSWR of no more than 2 when con-nected to a 50-ohm feeder. The frequency of 2 GHz was chosen as the central frequency in numerical studies. Cal-culations of the directional characteristics of the most successful variants of microstrip radiators within the matching band are given. It is shown that for a given ge-ometry and parameters of filling the substrate, the most broadband is a microstrip elliptical radiator, the matching bandwidth of which is from 1900 to 2100 MHz, i.e. +/- 5% of the center frequency. The results obtained can be use-ful both in the design of microstrip antenna arrays and in the construction of microstrip multiband antennas, which is especially important for new generation mobile com-munication systems.