PIN Diode-Enabled Reflector/Absorber with Out-of-Band Transmission

A PIN diode-enabled reflector/absorber with out-of-band transmission is proposed. First, an equivalent circuit model is developed to provide insight into the physical operation. Using the circuit model, a parametric study is provided demonstrating a tradeoff between reflector/absorber bandwidth and insertion loss in the transmission bands. Next, the desired response is demonstrated with a simulation model of a two-layer frequency selective surface. Transmission line theory is employed so that each layer can be initially modeled individually and fine-tuned by hand. Finally, the dynamic resistance of the PIN diode is leveraged to achieve the desired attenuation in the absorbing state. This approach provides electronic control of the attenuation level and simplifies the design by avoiding additional lumped resistors or lossy films.