Microwave magnetoelectric effects in ferrite-piezoelectric composites and dual electric and magnetic field tunable filters

Magnetoelectric (ME) effects at ferromagnetic resonance (FMR) in ferrite-piezoelectric layered structures have been investigated in lithium zinc ferrite (LZFO)-lead zirconate titanate (PZT) and yttrium iron garnet (YIG)-PZT. When an electric field E is applied to PZT, the piezoelectric deformation is transmitted to the ferrite and results in a shift in FMR. Data on the field shift caused by E are presented and compared with theory. Although the strength of ME coupling is weaker in YIG-PZT than in LZFO-PZT, the E-assisted field shift in YIG-PZT is much higher than the resonance line width and is potentially useful for filter applications. An electric field tunable YIG-PZT microwave band-pass filter based on ME effects at FMR is designed and characterized. The device can be tuned over a wide frequency band with a bias magnetic field and over a narrow band with a voltage applied across PZT. Data on tuning range, insertion loss, and device characteristics are presented.