BAE Systems PLC
Acoustic transducer

Abstract:

There is disclosed an acoustic transducer for communications within an operational bandwidth, the transducer comprising: A signal generator for generating a signal at a centre-frequency within the operational bandwidth; A piezoelectric element having a dielectric constant that varies with temperature; A driving electrode at the surface of the piezoelectric element; A matching network, having a natural frequency at a given temperature, and operable to transfer the signal from the signal generator to the piezoelectric element whilst mitigating electrical loss, the matching network being connected to the driving electrode; Wherein the matching network comprises a temperature compensating capacitor connected in parallel with the piezoelectric element, the temperature compensating capacitor being for counteracting temperature-induced changes to the dielectric constant of the piezoelectric element such that the electrical natural frequency of the transducer is substantially constant over a range of temperatures.