Microstrip Antennas

Several important developments are reviewed to trace the evolution of microstrip antennas since 1974. Munson‘s 1974 paper [l] seems to have been the beginning of an explosion of work that reports experimental and analytical developments in more than 1000 journal articles. Early developments were guided by the interpretations available from transmission line and cavity models, but later developments of full-wave moment methods provided more accurate analyses for design and development. The capability to obtain circular polarization from single elements and arrays has led to numerous applications in communications while stacked patch antennas utilizing parasitic coupling have done much to alleviate the small-bandwidth restriction of simple microstrip antennas. Coaxial probe and monolithic microstripline feeds have been supplemented by a variety of proximity feeds that provide design flexibility and offer performance alternatives.