Mixer-based subarray beamforming for sub-Nyquist sampling ultrasound architectures

Ultrasound imagers suffer from a large data rate between their analog to digital converter (ADC) front-end and digital beamforming backend. This becomes a limiting factor when the number of elements is increased, such as in modern 2D transducers. To address this issue, prior work considered sub-Nyquist sampling techniques that exploit the disparity between the signal´s physical bandwidth and innovation rate. In this work, we extend this framework using an analog-domain subarray beamforming technique that is feasible due to the narrowband nature of the sub-Nyquist signal acquisition. When applied to waveforms taken from a commercial ultrasound machine, this method reduces both the low-rate ADC count by a factor of eight and the total data rate by a factor of 54 with minimal image degradation.