The compound structures of frequency-selective-surface(FSS) and dielectric slab were investigated by computation

based on modal matching method

and experimentation

taking slot arrays as illustrative examples. Frequency responses of FSS structures by different compounding approaches were analyzed

including the influence of polyimide base film and adhesive coating with different thickness. The results show that the influence of base film and adhesive coating in FSS structures can not be neglected

and they have a close relationship with the compounding approach and dielectric thickness. The compound structure should contain adhesive coating to eliminate the effect of air gap. If dielectric constants of base film and adhesive coating are less than or close to that of the slab

and if the slab is over 10 times thicker than base film and adhesive coating

the influence of base film and adhesive coating on the transmission properties of properly compound structures would be minimized. The comparison of measurement and computation of frequency response of FSS structures

loaded with dielectric slab of a series thickness on one side

shows that the flaw of adhesion would change the transmission properties of FSS structures. All factors above-mentioned should be considered in FSS design.