Frequency-Selective Structures With Suppressed Reflection Through Passive Phase Cancellation

Multilayered frequency-selective structures with checkerboard arrangement are presented to demonstrate the application of passive phase cancellation to reduce the strong reflection from a traditional 2-D single-layer slot-type frequency-selective surface (FSS). The simple square slot is used as the basic unit to construct the involved supercells which are further combined to achieve the multilayered structures. The properly selected spacing between layers is mainly responsible for producing supercells with out-of-phase reflections, which establishes the destructive interference of reflected waves. In comparison with the traditional FSS, a band of reflection reduction is observed below the passband through the principle of phase cancellation. Meanwhile, the multilayered structures can maintain a passband with small insertion loss for transmission. The effect of increased supercell types on the bandwidth enhancement of reflection reduction and that of checkerboard arrangement on the angular performance are considered. A good agreement between simulation and measurement validates the observations.