Magnetostatic wave resonators

The purpose of this paper is an overview of recent advances about tunable two-port microwave resonators using the propagation of magnetostatic waves. These waves propagate in yttrium iron garnet films grown by liquid phase epitaxy on gadolinium gallium garnet substrates. 8 dB insertion loss magnetostatic surface wave resonators have been achieved with a loaded Q close to 450 and an out of band rejection of about 10dB. By decoupling the resonator from the transducers, Q values greater than 800 can be obtained with 15 dB insertion loss and a rejection of the off-resonance frequencies greater than 10 dB. Volume wave resonators have a higher Q value of about 1200 and 16 dB insertion loss for a rejection equal to 4 dB. Some experimental results on metal dot array cavity are presented and limitations related to power saturation, frequency versus temperature variations and off-resonance transmission are discussed.