| 摘要 |
PURPOSE:To miniaturize the surface acoustic wave resonator by forming a transducer comprising interdigital electrodes to a surface acoustic wave substrate having a small surface acoustic wave electromechanical coupling coefficient so as to set the interdigital electrodes in a prescribed range and to obtain a high Q with a few number of pairs. CONSTITUTION:On a crystal substrate 10 of 38 deg. rotation Y-cut X propagation, 300 pairs of normal or interdigital electrodes 11 having a pitch of nearly 25mum are formed. The electrodes are made of Al and the film thickness is taken as 1.5mum (nearly 3% of wavelength lambda0). The dimension of the interdigital electrodes 11 of the surface acoustic wave resonator is set as W/W+G=0.6-0.9, where W is the width of electrode finger of the interdigital electrodes, G is a pitch of adjacent electrode fngers of the interdigital electrodes and W+G is wavelength/2. The surface wave electromechanical coupling coefficient KSAW of the crystal substrate 10 is taken as <=10%, a high Q is obtained with a few number of pairs and the surface acoustic oscillator is miniaturized. |
