National Research Council of Canada. National Science Infrastructure
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII, 28 June - 1 July 2016, Edinburgh, United Kingdom
Low noise amplifier; cryogenic LNA; radio telescope receiver; square kilometer array; InP HEMT; UHF band LNA; hybrid microwave integrated circuit; MeerKAT
This paper demonstrates two designs of extremely low noise amplifiers in the low frequency range of 350 MHz to 1070
MHz. Hybrid microwave integrated circuit is adapted for a low noise design at this low frequency range. Discrete
passive components with high-Q and large values are selected to integrate with the best low noise transistors to optimize
the LNA performance. The first UHF band cryogenic LNA was designed with InP HEMTs in all three stages for Square
Kilometer Array - mid telescope band-1 receiver. This LNA extended the low end frequency to 350 MHz, and achieved
averaging 1.4 Kelvin of a record low noise temperature, more than 47 dB gain, and good input and output return losses <
-10 dB over the broad bandwidth from 350 to 1050 MHz at 15 K. The second UHF band cryogenic LNA was developed
for MeerKAT Array, a precursor of Square Kilometer Array. This LNA was designed with InP HEMT transistor at first
stage to achieve best low noise performance and GaAs HEMTs for second and third stages to replace InP HEMTs and
realize high gain and good amplitude stability at cryogenic temperature. The second LNA achieved a record low noise
temperature of averaging 0.6 Kelvin, more than 45 dB gain, and good input and output return losses ≤ -12 dB over the
wide bandwidth from 580 to 1070 MHz at 15 K.
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy VIII, 991420-3.