Dual-Band Frequency Selective Surface Based on Shunted SIW Cavity Technology

The design of a hybrid frequency selective surface (FSS) is presented based on the substrate integrated waveguide cavity (SIWC) technology. The intended design combines two FSS slots (multiapertures) based on the SIWC by sharing the adjacent vias of the unit cell to exhibit unique features in terms of their cavity designs and performance. The design consists of a circular slot with a circular cavity (named as Cavity-A) and a cross slot with a shared cavity with an adjacent unit cell (named as Cavity-B). As a result, the structure shows the dual-bandpass response with sharp roll-off performance characteristics. One band possesses narrowband characteristics at 8.12 GHz. Whereas, the next band with wide bandpass characteristics from 9.5 to 11.5 GHz. Further, the structure has shown a very low insertion loss (IL) of better than 0.15 dB in its operating bands. For proving the concept, a physical prototype has been fabricated, and its functionality verified. A good agreement has been found between the estimated and experimental results.