Simulation and Implication of a two-dimensional phased array flexible ultrasound system for tissue characterization

It has been demonstrated that phased-array ultrasound can be used for configuring spatial focal zone and perform noninvasive characterization of trabecular bone quality. Such a sensor configuration can also be integrated into existing ultrasound triggering, data analysis, mux, and imaging system in a flexible ultrasound platform. The primary goal of this study is focused on the unique dual 2-D array transducer kit design with 1MHz center frequency and simulation to a flexible ultrasound system for trabecular bone assessment. Transmission (Tx) and receiving (Rx) transducers are designed as two identical 2-D array sensors, with elements arrayed in 27*27 as a square. Element width is 1.05 mm and kerf is 0.2 mm. Tx elements are divided into sub-blocks to excite ultrasound signal in sequence to decrease the system complexity while maintaining beam pattern properties by the signal processing procedure at Rx side. Appropriate delay modules are inserted into the process of exciting signal. The working procedure is simulated by FIELD II program. The gray-scale simulation of acoustic resolution and side lobes are analyzed. The theoretical lateral resolution (LR) is 2.436 mm, with 2.8 mm in simulation. Hann window based apodization process shows the reduced side lobes. The results suggested that the reduced array size (27*27) simplifies the design and manufacturing, but maintains the image/signal resolution.