ABSTRACT
Cryogenically cooled ultra-low-noise amplifiers (LNAs) have had a profound impact on experimental science. These amplifiers allow us to study fundamental physical phenomena through low-temperature physics research, to communicate with spacecraft at distant planets, and to probe the history and contents of the universe through radio astronomy. Without these LNAs, countless experiments would have been impossible and areas of experimental physics simply could not exist. * Examples of Applications Requiring Cryogenically Cooled LNAs
Application
Frequency Range (GHz)
Comments
Radio astronomy
0.1–100
Microwave telescopes. 1–100,000,000 elements. Cryogenic cooling not always economic
0–5
IF amplifiers for superconductor-insulator-superconductor (SIS) mixers
0–3
IF amplifiers for HEB mixers. Requires very good input match to achieve good HEB stability. HEB IF bandwidth limited by thermal time constants
Deep-space comm.
8, 32
Current DSN link. Lower ground terminal system noise can be leveraged into either higher data rates or lower power transmitters/smaller transmit antennas
0–10
For use with optical communications system. Large signals. Jitter is critical
RFSQ logic
0–50
Superconducting computers. Interfacing circuitry to transition from low voltage Josephson-junction logic to room temperature logic
Low temp phys.
Varies
Sensor readout. Desired sensitivity can be on the order of the quantum limit (not yet practical)
