A high-frequency and high-frame-rate ultrasound imaging system design on an FPGA evaluation board for capacitive micromachined ultrasonic transducer arrays

Dynamic receive beamforming (DRBF) is challenging for field-programmable gate array (FPGA)-based ultrasound (US) imaging because it is computationally intense. Work has been done to either simplify the delay calculation or precalculate the delays and store them on the FPGA. The former sacrifices image quality and the latter is challenged by limited memory resource on the FPGA. In this work, we report on the design of a compact US imaging system for capacitive micromachined ultrasonic transducer (CMUT) arrays implemented on an FPGA evaluation board. The system features high frequency and high frame rate. It transmits ultrasound pulses centered at up to 20 MHz and can receive ultrasound echo signals up to 60 MHz. When working with a 16-element 2.48-mm CMUT array centered at 4.5 MHz, the system can perform conventional phased array (CPA) imaging at 170 FPS from a depth of 2.48 mm to 17.34 mm within a 90° sector. The system features full DRBF for every pixel.