On-wafer band-stop and band-pass microwave filters based on ferromagnetic resonance

This paper describes a new, on-wafer microwave devices based on high magnetization, metallic ferromagnets such as Fe and Permalloy. These devices are small and could be integrated with high frequency electronics. Reduction of device dimensions in these monolithic microwave integrated circuits is important from the cost and reliability point of view. We present here results for microwave band stop and band pass filters based on a microstrip geometry. These structures, prepared by sputtering on GaAs substrates, are compatible in size and growth process with on-chip high-frequency electronics. We observed power attenuation up to ∼ 100 dB/cm and an insertion loss on-the order of ∼ 2-3 dB for both Permalloy and Fe based structures.