Active frequency-selective rasorber with switchable dual operating modes

This letter presents an active frequency-selective rasorber (AFSR) with switchable dual operating modes at L-band. The proposed frequency-selective rasorber (FSR) comprises of a resistive layer and a frequency-selective surface layer loaded with PIN diodes, separated by an air spacer. The operating mechanism is elaborated by analyzing the equivalent circuit model. By controlling the states of the PIN diodes, the AFSR can be switched from the absorption-transmission-absorption (A-T-A) to absorption-reflection-absorption (A-R-A) modes. In the A-T-A mode, the transmission peak is 0.21 dB at 1.89 GHz, while the absorption band is 0.87 GHz to 3.42 GHz. In the A-R-A mode, the reflection peak is 0.15 dB at 1.91 GHz, while the absorption bands are (0.95 to 1.34) GHz to (2.1 to 3.51) GHz. A prototype of the proposed FSR was fabricated and measured to verify the design concept.