A New Type of Combined Element Multiband Frequency Selective Surface

It is well known that a multiband frequency selective surface (FSS) can be obtained by arranging multiple simple apertures in a periodic array. However, this simple combination can not achieve a perfect resonance response in a wide band due to the restriction of the grating lobe frequency determined by the array. A new type of element, the multi periodicity combined element (MPCE), is presented to solve this problem. Its feasibility on restraining the grating lobes is proven by numerical experiments and theoretical analysis. The electromagnetic performance of the MPCEs was studied. The results show that the MPCE FSSs have much weaker grating lobes than the traditional FSSs and their frequency performance can be well predicted through the properties of the member element FSSs. An approximate formula for predicting the transmission coefficients of the grating lobes is provided.