Insertion-phase-delay characteristics of bandpass FSS structures

The insertion phase delay (IPD) characteristics of frequency selective surface (FSS) loaded by solid half-wavelength wall are studied based on mutual admittance approach. IPD characteristics of FSS structures are compared with those of the loading dielectric, and the influences of some parameters are analyzed. An emphasis is laid on cross polarization, especially the depolarization effect at different polarization angles and incidence angles. Results show that one way for solving the problem of the cross polarization of the bandpass FSS structure is to maintain the consistency of resonant frequency in the two main polarizations (TE & TM), thus reducing the IPD difference between two polarizations.