The 311 anharmonic mode vibration SC-cut resonator excited by lateral field

The SC 301 and 310 mode resonators have been developed over past several years in Besancon (perpendicular field) and in Warsaw (lateral field). These resonators exhibit very interesting properties. The 311 mode of vibration is very suitable because of the fourfold symmetry of vibration. We expected that a resonator excited on this mode would exhibit more interesting properties. Thus, we tried to excite this vibration mode by a simple configuration of four lateral field electrodes but we observed in this case a very strong excitation of other modes. Then a XY table was developed with a lateral field electrodes configuration. Using this table, measurements of the 311 mode vibration distribution were carried out. These results were compared with X-ray topography vibrations measurements. Based on the measurement results, the lateral field electrodes configuration for 311 mode excitation was designed and models of the resonators were constructed. The paper presents the results of these investigations.