RESONANT-FREQUENCY OF A TUNABLE RECTANGULAR MICROSTRIP PATCH ANTENNA

The resonant frequency of a coaxial-probe-fed rectangular microstrip a ntenna tuned by a number of passive metallic posts suitably placed wit hin the antenna's boundary is obtained by using the resonant frequency expression in the absence of the post. The resonant frequency in the absence of the post is calculated from the fringing field extension an d effective relative permittivity expressions. The theoretical resonan t frequency results of tunable rectangular patch antenna obtained by u sing this method are in good agreement with experimental results avail able in the literature. (C) 1994 John Wiley & Sons, Inc.