Self-reciprocal calibration of micromachined capacitance transducers in air

A one-transducer self-reciprocal calibration method has been applied to a micromachined capacitance transducer in air over the frequency range 100 kHz/spl sim/700 kHz. The corrections for air attenuation and transducer diffraction effects at different frequencies are included in this extended reciprocal calibration technique. The measured receive sensitivities are validated by comparing with results obtained using a three-transducer calibration method. The self-calibration results are also validated by comparing with predictions from a theoretical model for the test transducer.