Design of front-end receiver for low noise ultrasound imaging system

• Main Author: Sun, Huaxi
• Other Authors: Zheng Yuanjin
• Format: Theses and Dissertations
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Control and instrumentation::Medical electronics
• Online Access: http://hdl.handle.net/10356/69564
• Institution: Nanyang Technological University

Ultrasound imaging has been widely used in industrial and biomedical applications. In general, high sensitivity of the front-end system is always wanted. The way of increasing the sensitivity is to increase the input signal and reduce the noise figure (NF) of the system that is dominated by NF of the first stage. Therefore the ultrasound transducer, the low noise amplifier (LNA) and the matching network between them are studied, resulting in the conclusion that conventional matching techniques are insufficient for voltage amplification or noise optimization. This thesis presents a novel way of input matching to increase sensitivity. Capacitors and inductors with negligible noise are used to pre-amplify the ultrasound signal and reduce NF by making the input-referred noise of LNA less significant. The front-end design includes transducer modeling, LNA design and co-design of input matching network. Ultrasound transducer model is successfully extracted by experiment with 95% accuracy. A LNA with 0.9nV per square root of Hertz input-referred noise is designed and simulated in standard 0.18μm process. The input matching technique is verified by simulations and experiments, showing that it can provide over 15dB voltage gain and 6dB signal-to-noise ratio (SNR) improvement. Related materials have been patented.