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PMUT
Piezoelectric micromachined ultrasonic transducers (PMUT) are MEMS MEMS (micro-electromechanical systems) is the technology of microscopic devices incorporating both electronic and moving parts. MEMS are made up of components between 1 and 100 micrometres in size (i.e., 0.001 to 0.1 mm), and MEMS devices ...-based piezoelectric ultrasonic transducers. Unlike bulk piezoelectric transducers which use the thickness-mode motion of a plate of piezoelectric ceramic such as PZT or single-crystal PMN-PT, PMUT are based on the flexural motion of a thin membrane coupled with a thin piezoelectric film, such as PVDF. In comparison with bulk piezoelectric ultrasound transducers, PMUT can offer advantages such as increased bandwidth (signal processing), bandwidth, flexible geometries, natural acoustic impedance match with water, reduced voltage requirements, mixing of different resonant frequencies and potential for integration with supporting electronic circuits especially for miniat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CMUT
Capacitive micromachined ultrasonic transducers (CMUT) are a relatively new concept in the field of ultrasonic transducers. Most of the commercial ultrasonic transducers today are based on piezoelectricity. In CMUTs, the energy transduction is due to change in capacitance. CMUTs are constructed on silicon using micromachining techniques. A cavity is formed in a silicon coating, substrate, and a thin layer suspended on the top of the cavity serves as a Acoustic membrane, membrane on which a metallizing, metallized layer acts an electrode, together with the silicon substrate which serves as a bottom electrode. If an alternating current, AC signal is applied across the current bias, biased electrodes, the Vibrations of a circular membrane, vibrating membrane will produce ultrasonic waves in the medium of interest. In this way it works as a transmitter. On the other hand, if ultrasonic waves are applied on the membrane of a biased CMUT, it will generate alternating signal as the capa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |