Hybrid multi/single layer array transducers for increased signal-to-noise ratio

Area of Science:

• Ultrasound Medical Imaging
• Transducer Technology
• Signal Processing

Background:

• Two-dimensional (2-D) array transducers are crucial for advanced ultrasound capabilities like dynamic focusing and high-speed volumetric imaging.
• Small element size in 2-D arrays leads to low signal-to-noise ratio (SNR) due to small capacitance and high impedance.
• Previous work demonstrated improved SNR with multi-layer PZT transducers.

Purpose of the Study:

• To investigate if a hybrid array configuration further enhances transducer SNR compared to conventional designs.
• To optimize the number of PZT layers for maximum transmit power in the hybrid array.
• To evaluate the impact of the hybrid configuration on pulse-echo SNR.

Main Methods:

• A hybrid array configuration was designed with a low impedance transmitter (10 Omega) and a high impedance preamplifier in the receive mode.
• A control configuration used a standard 50 Omega transmitter and direct coaxial cable connection.
• The KLM transmission line model was used to determine optimal PZT layers for a 5x102 hybrid array at 7.5 MHz.

Main Results:

• The KLM model indicated 9 PZT layers yield maximum transmit power for the hybrid array.
• Simulations showed a 23.7 dB improvement in pulse-echo SNR for the hybrid configuration over the control.
• The enhanced SNR allows for the use of low voltage transmitters.

Conclusions:

• The hybrid array configuration significantly improves ultrasound transducer SNR.
• This advancement facilitates the integration of low-voltage transmitters onto integrated circuits within the transducer handle.
• The findings pave the way for more compact and efficient ultrasound systems.