A wideband electronically tunable magnetostatic wave notch filter in YIG-GaAs waveguide structure

An electronically tunable microwave notch (band-stop) filter has been constructed in an yttrium-iron-garnet (YIG)/gallium arsenide (GaAs) material structure. An incident microwave propagating along the microstrip transmission line in the GaAs substrate is coupled to the magnetostatic surface waves excited in the YIG layer, which is laid upon the microstrip transmission line. Maximum coupling and thus the peak absorption of the output microwave power occur at the ferromagnetic resonance frequency in the YIG film as determined by a bias magnetic field. A tuning range as large as 1.6 to 13.6 GHz in the resonance frequency with the corresponding magnetic field tuning range of 70 to 4000 Oe has been accomplished.