A Magnetostatic Surface Wave Filter Tunable Over 8-32 GHz Realized in Thickness Scaled Yttrium Iron Garnet

This study presents a microfabricated magnetostatic wave (MSW) filter realized in a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$15 \mu ~\mathrm{m}$</tex> thick yttrium iron garnet (YIG) film, achieving a superior filter skirt at the upper passband edge and extending the operating frequency range to 32 GHz. The filter achieves 28 dB isolation at 0.9 times the bandwidth above the center frequency. Utilizing a two-cavity YIG structure with straight line transducers, an insertion loss of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2.5-5.4 ~\text{dB}$</tex> with isolation exceeding 28 dB from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$8-32 \text{GHz}$</tex> is demonstrated. Additionally, the filter exhibits larger bandwidth and power handling compared to filters realized in thinner YIG, with very small compression observed up to 10 dBm input power.