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本文提出了一种紧凑的可动浮栅型电容式超声传感器(Capacitive Micromachined Ultrasonic Transducer,CMUT)器件结构和低噪声高频电路。该结构包含通常CMUT上下电极和MOS晶体管。建模对浮栅型CMUT器件进行了直流分析和时变电容的瞬态分析,模拟结果表明该传感器结构比传统CMUT具有更低的寄生电容和输出阻抗。在1.5Pa超声声压下进行Cadence和ANSYS仿真,输出信号为40.1mV,在1MHz等效输出噪声为16.59nV/Hz1/2,直流增益为74.73dB,单位增益带宽为488MHz。指标优于传统的CMUT结构,具有医学三维成像的应用前景。
In this paper, a compact structure of capacitive micromachined Ultrasonic Transducer (CMUT) and a low noise high frequency circuit are proposed. The structure contains the usual CMUT upper and lower electrodes and MOS transistors. The DC-transient analysis and time-dependent transient analysis of the floating-gate CMUTs are carried out. The simulation results show that the sensor structure has lower parasitic capacitance and output impedance than the conventional CMUTs. The Cadence and ANSYS simulations were carried out under 1.5Pa ultrasonic pressure, the output signal was 40.1mV, the equivalent output noise was 16.59nV / Hz1 / 2 at 1MHz, the DC gain was 74.73dB and the unity gain bandwidth was 488MHz. The index is superior to the traditional CMUT structure and has the application prospect of medical three-dimensional imaging.