Tunable and broadband radar absorber based on PIN diodes controllable FSS

In this paper, we proposed a dynamically tunable broadband microwave absorber based on active frequency selective surface (AFSS). The unit cell of the AFSS is composed of PIN diode and two reverse anchor patches. When the bias voltage of PIN diode is changed between 0.6 and 0.78 V, the reflection coefficient of the absorber can be less than -10 dB from 7 to 13 GHz, and the absorbing frequency band can be tuned within the specific range. The fabricated AFSS absorber is light, thin enough and achieves a broad tuning bandwidth. It has the potential to be applied in smart radar absorbing materials.