Reconfigurable bandpass filter based on SSPP and SIW used in radar system

Abstract In this paper, a hybrid circuit for spoof surface plasmon polaritons (SSPPs) and substrate integrated waveguide (SIW) to implement reconfigurable bandpass filter devices is reported. The hybrid circuit consists of reconfigurable corrugated metal strip and SIW. The upper cut-off frequency is controlled using SIW modulation, and the lower cut-off frequency of the filter is adjusted using capacitors. We demonstrate that ultra-broadband conversion can be achieved by tuning the geometric parameters of the SIW and the capacitance of the SSPP waveguide. Simulated and experimental results show good agreement for the fabricated hybrid circuit, exhibiting reconfigurable passbands ranging from 10 to 19.64 GHz (96.4%), out-of-band rejection up to 45 dB, and transmission loss below 2.36 dB. The proposed filter exhibits excellent performance, including a wide passband and low loss. The proposed hybrid circuit bandpass filter offers great potential for accelerating the development of integrated circuits and plasmonic devices at microwave and terahertz frequencies, while suitable for radar system applications.