Computation and optimization of resonant frequency and input impedance of a coax-fed circular patch microstrip antenna

Microstrip antennas are important elements of today's wireless communication networks. In their various applications, it is critical to provide wide band operation around the resonant frequency providing good impedance match between the antenna element and the feed. In this study, new, simple, and accurate computation of resonant frequency and input impedance of double-layered, coaxial fed circular disk microstrip antenna with air gap is performed. In the analysis, new effective radius and permittivity expressions are used in simple and modified form including modal effects. Then, a new approach is proposed to provide input impedance matching at resonant frequency via the application of microgenetic algorithm for wide band operation. The accuracy of theoretical calculations and impedance matching approach are presented for various structural parameters and operational modes of the antenna.