Tunable Q matching networks for capacitive ultrasound transmitters

Airborne capacitive micromachined ultrasonic transducers (CMUTs) have predominantly large input reactance with small series radiation resistance. To maximize the acoustic power at resonance we employ low cost LC matching networks between output impedance driving source and CMUT transducer. Conventional networks, including pi T-network topologies are employed to provide a high-Q match. An important free parameter that controls bandwidth of match in T-networks is center impedance. Since simple pi-network can be formed from two basic L-sections, L-sections provides control over Hence these tunable-Q networks. We use lumped circuit model derive resonance. At equivalent transducer reduced RC consisting resistance transducer’s capacitance only. From determine inductance capacitances various The aim cancel cell cell’s report significant improvement radiated when driven using proposed schemes.