Chapter 10 – Planar Magnetic Devices for Signal Processing in the Microwave and Millimeter Wave Frequency Range

Abstract We present a review of theoretical and experimental results for tunable microwave devices using a variety of magnetic thin films and layered structures. These devices are compatible in size and growth process with on-chip high-frequency electronics. For devices based on metallic ferromagnetic films of Fe and Permalloy, the operational frequency ranges from 5 to 35 GHz for external fields below 5 kOe. Hexagonal ferrites can lead to devices operating in the 35–70 GHz range. We explore a variety of devices including band-stop filters, phase shifters, nonlinear devices, nonreciprocal devices, and electrically tuned devices.