Near-Optimal Radiation Patterns for Antenna Diversity

A recent method has been proposed for determining the optimal radiation characteristics of antennas that maximize the diversity gain for a given antenna aperture and power angular spectrum of the incident field. However, because this approach results in antennas whose current distributions overlap in the aperture, it is difficult to achieve the radiation characteristics using practical designs. This paper proposes several methods that construct the near-optimal radiation characteristics assuming the apertures representing distinct antennas are disjoint. Computational results show that the average diversity performance achieved for these approximate radiation characteristics is roughly 1.3 dB below that achieved using the optimal patterns.