ULTRASCHALL-SIGNALWANDLER MIT SCHWINGUNGSMEMBRAN MIT KAPAZITIVEM BREITBANDEFFEKT

摘要

The invention relates to an ultrasonic transducer with a vibrating membrane with capacitive effect (1), comprising: - a support (13) with a cavity (14) is provided; - a vibrating membrane (11) fixed to the support (13) and covering the cavity (14); -a conductive element (101) separated from the membrane (11) by the cavity (14); -characterized in that: -the vibrating membrane (11) has a resonance frequency in membrane mode fm and a resonance frequency in plate mode verifying the relationship fm> fp; -an excitation circuit (2) has terminals connected between the vibrating membrane (11) and the conductive element (101), and configured to apply between its terminals an electrical signal whose maximum frequency fo verifies the relationship fm> 1.5 ^∗ fo; or a measurement circuit (3) is connected between the vibrating membrane (11) and the conductive element and configured to measure the variations in capacity up to a frequency fo.