Low Frequency Absorption-High Frequency Transmission Tunable Frequency Selective Rasorber

In this paper, a frequency selective rasorber (FSR) with broadband absorption at low frequency and tunable transmission at high frequency is proposed. The top layer is loaded with double curved line structure to realize low frequency resonant absorption and high frequency lossless transmission. The bottom layer adopts an active band-pass frequency-selective structure. By loading varactor diodes, the frequency of transmission peak can be tuned continuously in a wide band. Simulation results show that for x-polarized wave, the -10 dB absorption band is 3.1 to 6 GHz. For y-polarized wave, the -10 dB absorption band is 3.1 to 6.6 GHz. The transmission peak of the FSR can be continuously tuned from 8 to 16.8 GHz, and its transmission coefficient is between -3.2 and -0.8 dB. The design has a broad application prospect in the field of stealth and multi-frequency transmission of active radar radome.