Metasurfaces for Filter Miniaturization and Out-of-Band Rejection Improvement

This work presents a novel implementation of metasurface filters with high performance and compact size for future space applications. A $K$ -band fourth-order metasurface filter is proposed with a center frequency of 18.5 GHz and bandwidth of 400 MHz with an out-of-band rejection that is better than 30 dB over the range of 20–50 GHz. The proposed filter has a measured insertion loss of 1.47 dB and a quality factor of 670. The resonators implemented in this filter exhibit a miniaturization of 63% when compared to a conventional rectangular waveguide (RWG) resonator. The compact size and high-performance capabilities make the proposed filter an ideal solution for space applications.