Multiple-Frequency Design for High Performance Ultrasonic Measurement by Using Phased Array with Reduced Number of Sensor Element

Frequency design for high performance ultrasonic measurement is discussed by using phased array sensing with a reduced number of sensor elements. Multiple-frequency measurement technique has enabled a sparse array to realize a ghost-suppressing ultrasonic imaging owning to frequency-tunable piezoelectric sensors. The sparse phased array generates ghost in conventional one frequency measurement, and the second frequency is designed to suppress the ghosts and side lobes for high performance ultrasonic measurement. Frequency design procedures are introduced with considering the tunability of the micro sensors and an aspect of a view angle is added in them. The new design procedures have improved to enable more flexible steering angle ranges.