A CMOS Low Noise RF Front-End for Medical and Biological Imaging

Low noise analog front-end is an important part of ultrasound imaging equipment. This paper presents an RF front-end integrated chip, which consists a low noise amplifier, a mixer and a voltage controlled oscillator (VCO). The front-end is designed for high frequency ultrasound imaging, which realizes the expansion of the original ultrasound imaging frequency band. Based on the innovative chip architecture composed of the mode-switch voltage controlled oscillator and the wideband low noise amplifier (LNA), the wideband RF signal would be converted to 60 MHz for traditional ultrasound frequencies and detected by low-pass filtering and further digital processing. The LNA achieves a noise figure of 2.6dB, a voltage gain of 15dB, the mixer achieves a noise figure of 7.3dB, a convert gain of 10dB, the VCO achieves a $70 \%$ tuning range across $2.2-4.6 \mathrm{GHz}$, phase noise of $-126 \mathrm{dBc} / \mathrm{Hz}$ at 1 MHz offset. Finally, the extended application of ultrasound imaging frequency band is realized through this design.