Transmitting CMUT arrays without a DC bias

This study focuses on design, simulation, fabrication and measurement of transmitting CMUT arrays with unbiased mode of operation. We presented a design procedure considering the radiation pattern, Rayleigh distance and the parameters of the large signal equivalent circuit, which can be applied for different operation frequencies and applications. Large signal equivalent circuit model is used for lumped-element simulations. Harmonic balance and transient analyses are carried out with Gaussian enveloped tone burst, sinusoidal and pulse width modulation (PWM) signals with different duty cycles. Outputs of these simulations are fed in beamforming toolboxes for further verification. According to the design specifications transmitting CMUT arrays are fabricated. Corresponding experimental impedance measurements are conducted.