Magnetostatic surface wave resonators with metal edge reflectors

In magnetostatic wave (MSW) resonators based on rectangular yttrium-iron-garnet (YIG) films, straight edges serve as reflectors. In the configuration, width modes are often seen to interfere with the main resonant peak, splitting it. The occurrence of higher width modes is mainly due to the nonuniformity of the internal bias magnetic fields near the corners of the YIG film, leading to a coupling between the principal mode and the higher width mode. To prevent the coupling from occurring, metal films are deposited on both ends of the rectangular YIG film. An experiment on a resonator with metal edge reflectors shows that the resonant peak cannot be split, but that spurious resonances due to undesired higher modes occur. A multibar transducer is used to prevent the excitation of the undesired modes