MSW frequency selective limiters at UHF

Frequency selective limiters (FSLs) have potential application in maintaining the dynamic range of RF receivers in the presence of interference. Stripline FSLs, fabricated using thick YIG films, have been described previously and are suitable for broadband, microwave applications. Here a magnetostatic wave (MSW) FSL operating in the 400 MHz to 800 MHz frequency range is described with frequency selectivity and threshold power levels 100 times lower than achieved with stripline devices. Y₃Fe_(5-x-y)Ga_xSc_yO₁₂ (ScGaYIG) films with reduced 4πM and anisotropy field were grown by LPE and characterized for ΔH, ΔH_k and 4πM Devices were characterized for insertion loss, threshold power level, limiting, frequency selectivity and intermodulation products. FSLs in UHF through S-band (400 MHz to 4 GHz) are feasible with present YIG and ScGaYIG materials. Threshold power levels <20 dBm, narrow selectivity bandwidth <2 MHz and low intermod levels have been demonstrated.