An aperture coupled circular patch antenna operating at higher-order mode for HIPERLAN application

This paper presents the design of patch antennas for possible use in the 5 GHz-band HIPERLAN and NII wireless local area networking systems. In order to communicate with a base station or a peripheral unit, the radiation pattern of these antennas should be symmetrical in azimuth with the minimum in the zenith direction. A circular patch operating in the TM₀₂ mode can be used to obtain such a radiation pattern. An aperture coupling and a coaxial probe are investigated as possible feeding mechanisms for the patch antenna operating in the TM₀₂ mode. A full-wave analysis method is used to predict the two antennas performance in terms of return loss, input impedance, gain and radiation pattern. The effects of higher order modes and a finite ground plane on the radiation pattern are discussed