The RCS of a microstrip patch on an arbitrarily biased ferrite substrate

The radar cross section (RCS) of a rectangular microstrip patch on a lossy biased ferrite substrate is investigated. The analysis is based on a full-wave integral equation formulation in conjunction with the method of moments. In the analysis, the direction of the bias field is not prescribed. The RCS characteristics, especially the resonance behavior of a patch with various biasing conditions, are studied and compared to those for an unbiased ferrite. It is found that the resonant frequencies of a patch vary significantly with the change of the bias field, except for those resonant modes which have a dominant magnetic-field component in the direction of the bias field. This phenomenon is explained with a waveguide cavity model, and provides an independent check of the analysis. It is found that the magnetic loss affects the RCS at resonances significantly