Design And Test Of 32 Channel CMUT Ring Array Transceiver Circuit

With the wide application of ultrasonic imaging system in medical field,all kinds of ultrasonic transducer probes have become the focus of research at home and abroad.The traditional piezoelectric ultrasonic sensor is difficult to achieve a greater breakthrough due to the limitations of the manufacturing process,but the new ultrasonic transducer based on MEMS technology has the advantages that the traditional piezoelectric sensor does not have,and is expected to replace the traditional piezoelectric sensor in the ultrasonic probe market.At present,the new ultrasonic transducers based on MEMS technology mainly include CMUT transducer and PMUT transducer,compared with PMUT transducer,CMUT transducer has the advantages of wide bandwidth,high sensitivity and low acoustic impedance.The CMUT devices are fabricated into a CMUT ring array by special arrangement in the laboratory,the CMUT ring array is used as an ultrasonic probe to study its sound transmitting and receiving characteristics.This paper mainly designs the front-end circuit of CMUT ring array,and uses the front-end circuit combined with CMUT ring array to carry out transmission experiment,reflection experiment and one transmitter and multiple receivers experiment to verify the performance of the front-end circuit and CMUT ring array.By investigating the research status of CMUT devices and front-end circuits at home and abroad,the structure,working principle and equivalent circuit model of CMUT devices are summarized.The DC voltage setting,AC voltage setting and power supply coordination of CMUT devices are analyzed in theory.The parameters of CMUT ring array fabricated and tested in the experiment is tested to provide reference for circuit design and experimentThis paper focuses on the design and experimental test of 32 channel CMUT ring array transceiver circuit.Through the device test,the impedance,bandwidth and other parameters of CMUT ring array are obtained.Combined with the working principle of CMUT ring array,the pulse transmitting circuit based on FPGA and the receiving circuit based on transimpedance amplifier circuit are designed to realize the driving of CMUT ring array and the detection of echo signal.At the same time,the T / R isolating switch in the DAC chip is used to isolate the pulse signal,which is also the key to the design of the integrated circuit.The function and consistency test of 32 channel transceiver are carried out by building the test platform.Then,CMUT ring array is driven by transceiver circuit,and its echo signal is detected.Transmission experiment,reflection experiment and one multi receiver test are carried out respectively.The experimental results show that the transceiver circuit can achieve the given function,and the 32 channel transceiver circuit has good consistency.The transceiver circuit can drive the CMUT ring array and detect the echo signal of CMUT ring array.It is verified that the ultrasonic signal emitted by CMUT ring array has good transmission and reflection ability in water,and the feasibility of the application of transceiver circuit and CMUT ring array in ultrasonic imaging system is proved.