Study of switchable Luneburg lens reflector based on active frequency selective surface

In this article, a transmission and reflection states switchable Luneburg lens (LL) reflector based on active frequency selective surface (AFSS), namely LL‐AFSS reflector, is proposed. The reflector is composed of a miniaturized AFSS reflector, which can change the working state, and a LL composed of six layers and five media from inside to outside. By changing the bias voltage of the PIN diode loaded on the AFSS reflector, the transmission and reflection working states of the LL reflector can be freely switched in the frequency range of 3.5–5 GHz. When the PIN diodes are in ON state, the incident electromagnetic wave will not be reflected through the LL reflector. When the PIN diodes are in OFF state, the radar cross section (RCS) generated by the LL reflector to the incident electromagnetic wave reaches about 15 dB within the angle range of −30 ≤ φ ≤ 30°. The electromagnetic numerical simulation and experimental sample verification of LL‐AFSS reflector are carried out. The results show that the proposed design method is feasible and the RCS changes of transmission and reflection characteristics of LL reflector are obvious.