Signal reception method of capacitive Lamb wave device

A Capacitive Interdigital Transducer (CIDT) was used in capacitive Lamb wave device to solve the problem that the processes of function layers in most Lamb wave devices were incompatible with classical IC process. In the devices, CIDT were used as both excitation cell and reception cell of Lamb wave, as it was possible to realize the miniaturization. Because of CIDT's exciting and receiving the anti-symmetrical modes of Lamb wave directly, the problem of energy-coupling efficiency of transducers was solved. Basing on the analysis of several capacitance detecting circuits, the direct current circuit method was selected to meet the special demands of the device. In order to validate the application feasibility of direct current circuit method, a vibration-detecting experiment was designed. Experimental results show that the error between measurement vibration signal and its theory value is only 2.4%.