Title: Ultra-Low Noise Amplifier Design for Magnetic Resonance Imaging systems,
Abstract: This paper demonstrates designing and developing of an Ultra-Low Noise
Amplifier which should potentially increase the sensitivity of the existing
Magnetic Resonance Imaging (MRI) systems. The Design of the LNA is fabricated
and characterized including matching and input high power protection circuits.
The estimate improvement of SNR of the LNA in comparison to room temperature
operation is taken here. The Cascode amplifier topology is chosen to be
investigated for high performance Low Noise amplifier design and for the
fabrication. The fabricated PCB layout of the Cascode LNA is tested by using
measurement instruments Spectrum Analyser and Vector Network analyzer. The
measurements of fabricated PCB layout of the Cascode LNA at room temperature
had the following performance, the operation frequency is 32 MHz, the noise
figure is 0.45 dB at source impedance 50 {\Omega}, the gain is 11.6 dB, the
output return loss is 21.1 dB, and the input return loss 0.12 dB and it is
unconditionally stable for up to 6 GHz band. The goal of the research is
achieved where the Cascode LNA had improvement of SNR.