Comparison of microstrip antennas on ferrite and chiral substrates

The performances of microstrip antennas printed on either normally biased ferrite substrates or chiral substrates are compared. Results for both isolated elements and infinite arrays are presented. For the ferrite substrate case, several new and interesting results are discussed, including the generation of circular polarization using a single feed point, the reduction of antenna radar cross section, and dynamic wide angle impedance matching for a phased array. By contrast, there does not appear to be any significant advantage to using chiral substrates for microstrip antennas. In fact, the surface wave efficiency and cross-pol levels for microstrip antennas on chiral substrates are typically worse than for a comparable ordinary dielectric substrate. Results are obtained from full-wave moment method solutions for isolated probe-fed patches and infinite arrays, which have been formulated for both the normally biased ferrite and the chiral substrate cases.<>