Front-End Receiver Architecture for Miniaturised Ultrasound Imaging

Abstract

-The design and measured results for an I/Q synthetic aperture beamforming front-end are presented. The system targets a highly portable ultrasound imaging applications such as wearable/portable devices and capsule endoscopes. Synthetic aperture beamforming is carried out in the baseband in order to minimise the bandwidth and power consumption. A single-channel analogue front-end (AFE) demodulates RF signals into I/Q components. The FPGA-based beamformer dynamically apodises and focuses the data by interpolating and applying complex phase rotations to the I/Q samples. The entire system is pipelined using a synthetic aperture protocol through a single, multiplexed channel in order to reduce the cost and complexity of the system and minimise the area. The AFE consumes 7.8mW and occupies 1.5 mm × 1.5 mm in AMS 0.35µm CMOS. The digital beamformer is implemented on a Kintex-7 TM FPGA and consumes 262mW for a frame rate of 4Hz. Measured results using real ultrasound data reveal that comparable image quality may be attained to the case when full RF beamforming is used. Future work includes integration of analogue/digital components on a single chip.