Finite ground plane effects on the radiation pattern of small microstrip arrays

The radiation characteristics of microstrip antennas consisting of two patc h elements on small size substrates are studied by means of an approximate solution technique. Special attention is paid to the shielding effect due t o finite ground plane diffraction, Experimental and theoretical results sho w that the back radiation is influenced by the sidelobe level and can furth er be reduced when the antenna is boxed. For a correct radiation pattern co mputation these diffraction effects need to be included in the design of sm all array as well as in that of single element antennas.