Single‐phase unidirectional magnetostatic forward volume wave transducer using internal metal reflective arrays

Abstract

AbstractThis paper describes the experimental results of a single‐phase unidirectional magnetostatic forward volume wave transducer (MSFVW); this transducer effectively utilizes the reflections of metal strips placed asymmetrically in it. To design a single‐phase unidirectional transducer having internal reflectors, it is necessary to know the reflection characteristics of the metal strips but no study has been performed as yet to find the magnitude and phase of the reflection coefficient. Here, the reflection characteristics of a metal strip array for MSFVW are studied experimentally. For the single strip electrode, the reflection coefficient is in the range of 0.3 – 0.4, which is about one order higher than the value for surface acoustic wave (SAW) devices. Then it is shown for the first time that by properly utilizing the metal strip reflections, a unidirectional transducer can be realized without attaching an external phase shifter. The directivity of 13 dB was obtained for a transducer using four reflecting strips (which is a large value of directivity by a comparatively small number of elements). The phase of strip electrodes as determined from the direction was −90 deg, which is 180 deg different from the SAW devices.