Tilt-Optimized YIG Film-Based Magnetostatic Wave Tunable Bandpass Filters with Spurious and Passband Ripple Suppression

Reconfigurable filters with low loss and wide tuning range are crucial for future wireless communication systems. Yttrium iron garnet (YIG)-based magnetostatic surface wave (MSSW) filters provide these advantages but commonly suffer from strong spurious responses caused by width modes in thin-film cavities. This work designs a tilt-optimized YIG film cavity that suppresses width spurious modes and passband ripple in MSSW filters by rotating the YIG cavity relative to the straight-line transducers. Finite-element simulations and experimental results show that an optimal tilt angle (~35°) suppresses the spurious resonances, smooths the passband, maintains low insertion loss and steepens the filter skirts over a wide tuning range of 3–20 GHz. The tilted geometry offers a simple, microfabrication-enabled approach for high-performance YIG filters in next-generation (6G) reconfigurable RF front-ends.