Radiation pattern of microstrip antenna arrays on finite substrates

A method to compute the radiation pattern of microstrip antenna arrays on substrates of finite lateral extent is developed. Using the Green's function of an infinite dielectric slab, volume polarisation currents are introduced. With an assumed current distribution on the radiating patches the electric currents on the ground plane are calculated by the method of moments. The presented theory is illustrated for the example of a 2/spl times/2 patch array.