RESONANT CHARACTERISTICS OF FREQUENCY SELECTIVE SURFACES ON FERRITE SUBSTRATES

The resonant characteristics of frequency selective surfaces (FSSs) on in-plane biased ferrite substrates for the TE polarization are described. An approximate formula for evaluating the resonant frequency is presented. The tunable property of the resonant frequency of a dipole FSS is flrstly demonstrated by the results obtained from the moment method (MM) and the waveguide simulator measurement. Then the approximate formula is validated by the MM as well as measured results already published in a previous paper. It is interesting to note that two separate resonances occur at any magnetic bias fleld, and both increase as the magnetic bias fleld increases. The fractional tuning range is investigated based on the approximate formula. The results show that it increases as the saturation magnetization increases and decreases as the center frequency increases.