Actively tunable rasorber with broadband RCS reduction and low infrared emissivity

In this paper, an actively tunable rasorber with broadband RCS reduction and low infrared emissivity is proposed. The rasorber can achieve flexible control of the peak of the transmission frequency and make the platform invisible in multiple spectrum. Based on the combination of varactor diodes and bandpass frequency-selective surface (FSS), the transmission window can be continuously tuned from 1.8 to 4.5 GHz. The designed rasorber has more than 10 dB RCS reduction from 5.4 to 14.1 GHz. Furthermore, an infrared low emissivity layer based on ITO resistance film is added above the rasorber, and the average infrared emissivity of the measured surface is 0.33. The experimental and simulation results are in good agreement. This work is expected to be applied to frequency hopping secure communication and ultra-wideband, multi-spectrum stealth.