Effect of a cavity enclosure on the resonant frequency of inverted microstrip circular patch antenna

The inverted microstrip circular patch (IMCP) antenna has been analyzed very recently by the present authors and the same microstrip structure enclosed in a cylindrical cavity has been employed by others to develop various active integrated antennas. In this paper, the effect of the cylindrical enclosure in changing the resonant frequency of an IMCP has been studied both theoretically and experimentally. The cavity-effect critically depends on the enclosed patch and the cavity dimensions which are thoroughly investigated to help a designer in choosing the antenna parameters. An efficient analytical formulation is also proposed to predict accurate resonant frequencies of the cavity enclosed IMCPs and is verified with different experimental data.