Low-Cost, Wideband Ultrasonic Transmitter and Receiver for Array Signal Processing Applications

This paper presents a low-cost, wideband ultrasonic transmitter for in-air ultrasonic applications based on a conventional narrowband piezoceramic transducer with an L-R circuit modification. An analytic method for calculation of the optimum circuit parameters for bandwidth expansion of the ceramic ultrasonic transmitter is described, together with experimental data proving the viability of the method. A low-cost wideband ultrasonic receiver array is also presented. The results of the first characterization of microelectromechanical systems (MEMS) microphones in the ultrasonic band and their use in a sensor array for ultrasonic array signal processing applications is also presented. The paper presents examples of prototype transducer performance in ultrasonic indoor applications.