Improving radiation-pattern distortion of a patch antenna having a finite ground plane

This paper presents a very useful and yet simple method of improving the radiation-pattern distortion of a patch antenna having a finite ground plane. The improvement can be achieved by cutting out the edges of the finite ground plane. This produces a phase shift between the induced equivalent magnetic currents on the edges, thereby causing cancellation in the diffracted fields. We numerically and experimentally examined the effects for some typical patch antennas and confirmed that the ripples in the copolar E plane pattern could be eliminated by using this approach.