ANALYSIS OF COPLANAR WAVE-GUIDE-FED MICROSTRIP ANTENNAS

A moment method analysis of a microstrip antenna fed by an open-end co planar waveguide is presented. The surface electric current on the mic rostrip antenna is represented by the entire domain basis functions, w hile the surface magnetic currents in the open-end slot and in the slo ts of the coplanar waveguide near the open end are expanded by the sub sectional roof-top basis functions. Some practical numerical aspects a re carefully discussed, and a numerical device is introduced to reduce the computation time for the integrals involving roof-top basis funct ions and the spectral-domain Green's function. The solution accuracy i s thus improved. Computed results for the reflection coefficients and input impedances are given and compared with measured values. Good agr eement between theory and experiment is obtained.