Characteristics of microstrip antennas with a superstrate

A method of analyzing and/or improving printed circuit antenna performance by the addition of a superstrate (cover) layer has recently been discussed for the case of a Hertzian dipole [1]. In this paper, the characteristics of rectangularly shaped microstrip antennas involving a superstrate are investigated using the method of moments. Results for center fed microstrip dipoles as well as microstrip antennas excited by electromagnetic coupling from a microstrip transmission line are presented. Mutual coupling is also discussed and the effect of the superstrate layer on microstrip antenna parameters is analyzed.