Miniaturized dualband loaded frequency selective surfaces with close band spacing

A novel dualband miniaturized bandpass loaded frequency selective surface (FSS) using substrate integrated waveguide technique (SIW) is presented. By loading surface mount capacitors, the size of the FSS is reduced to 6.6% compared with the resonance wavelength. By loading different lumped elements, closing band spacing can be easily achieved. The undesired coupling between LFSS unit cells is eliminated by using SIW technique, this way also can be used in conventional FSS design for cutting off the interference between the unit cells.