| The Lamb wave type of high frequency resonator was proposed. But any Lamb wave resonator operating really above 3 GHz, which is difficult to be realized with conventional surface acoustic wave (SAW), have been not reported. Authors have tried to realize the high frequency device by using A$_{1}$ mode of Lamb wave propagating in the X-axis direction on Z-cut thin LiNbO3 film deposited by chemical vapor deposition system (CVD) having high velocity and high electromechanical coupling factor. As the result, authors have realized a 4.5 GHz high frequency Lamb wave resonator with high velocity of 14,000 m/s, large impedance ratio of 52dB, and wide bandwidth of 7.2 % composed of thin LiNbO3 epitaxial film/air-gap/substrate for the first time. Also it is found that the thin LiNbO3 film is twined crystal. It is confirmed theoretically and experimentally that the spurious responses such as SH0 mode can not be excited because of twined crystal effect. |