A Thin and Broadband Tunable Radar Absorber Using Active Frequency Selective Surface

We present a thin and broadband tunable radar absorber using active frequency selective surface (AFSS). The AFSS is composed of a patch type frequency selective surface (FSS) and a PIN diode array. We investigate the impacts of the applied voltage of the PIN diode array and the size of the absorber. Our measurements show that the reflectivity of the absorber can be dynamically adjusted by changing the bias voltages. A good absorption property is observed at the bias voltage of 5 V, with the reflectivity below -10 dB over a frequency band of 5.3-13 GHz, and the thickness is only 5.3 mm.