Resonant frequency of microstrip antenna with multi-dielectric superstrates

In aerospace and other applications, microstrip antennas may be covered with multi-dielectric superstrates for protection against heat and environment hazards. During flight or in severe weather conditions, an additional superstrate may be naturally formed on its cover. In the design of such structures, the accurate determination of its resonant frequency is important due to the inherent narrow bandwidth of microstrip antennas. However, works reported are mostly limited in the case with one dielectric superstrate. An accurate computation for the resonant frequency of a microstrip antenna with multi-dieiectric superstrates is presented by means of the spectral domain immittance (SDI) approach and by improvements in numerical evaluations of integrals. Some useful conclusions have also been achieved.<>