A 4–18 GHz Tunable Magnetostatic Surface Wave Nonreciprocal Filter with Zero-Static-Power Consumption Optimized for High Out-of-Band Rejection

This work demonstrates a highly selective, 4–18 GHz tunable magnetostatic surface wave (MSW) filter based on Yttrium Iron Garnet (YIG) with an integrated zero-static-power magnetic bias circuit. The filter achieves low insertion loss below 5 dB, high out-of-band rejection between 38 and 66 dB, and nonreciprocal isolation greater than 31 dB, while maintaining a narrow 3-dB bandwidth and a 20-dB shape factor between 1.98 and 3.33. Optimized meander-line transducers and a tapered YIG waveguide suppress spurious modes and improve selectivity. Measured power handling and linearity includes an input 1-dB compression point exceeding 8 dBm and an in-band third-order intercept point (IIP3) of approximately 26 dBm.