A rigorous analysis of a microstripline fed patch antenna

A rigorous solution to the problem of a rectangular microstrip antenna fed by a microstripline is presented. The currents on the feed line and the patch are expanded in a suitable set of modes, and a moment method solution is formulated in the spectral domain. Three special feed cases are treated: a patch fed at a radiating edge; a patch fed at a nonradiating edge; and a proximity coupled patch. Good results are obtained for the radiating edge fed case and the proximity coupled case. The nonradiating edge fed case results were not as good; reasons for this discrepancy are discussed. Calculations are compared with measurements for high and low dielectric constant substrates.