Ultra-Low Noise Receive Systems

Miniature Cyrogenic Low Noise Amplifiers

The latest addition to Callisto’s range of cryo LNA products is our Miniature X-Band. This LNA is intended for use on tracking X-band ground station antennas operating around 8 GHz for reception. The LNA has two operating modes; normal and “turbo”. The difference between the two modes is the noise figure performance. In “turbo” mode the noise figure is significantly reduced compared to “normal” mode by cryo-cooling the LNA circuit. The intended application of this LNA is for critical data communications. By switching to the “turbo” mode the User can counter-act the effects of fading on his communications link by the improvement in his ground terminal G/T. When the link has returned to normal conditions the LNA can be switched back to “normal”, the cryo-cooler is switched off and the LNA circuits work at ambient temperature. A typical fade event can be caused by severe weather, for example. Another application for this dual mode LNA could be for ground stations used for in-frequent critical operations such as LEOP.

Cooling of the LNA circuit to very low temperatures is achieved using a miniature Stirling cycle cryo-cooler. These high efficiency refrigerators have been developed to serve various applications most notably for Infra-Red detector cooling in military equipment. As such, these miniature cryo-coolers are designed for high reliability and robustness.

Outline RF Specifications

Parameter

Specification

Frequency Range8.0 – 8.5 GHz
Overall gain> 38dB
Noise Figure Normal Mode1.1 dB (80K)
Noise Figure Turbo Mode0.4 dB (28K)
Input VSWR2.0:1
Output VSWR2.0:1
Output Power1dB CP +5dBm

Outline Interface Specifications

Parameter

Specification

Input InterfaceWR112 W/G
Output InterfaceSMA
Environment temperature-40°C to + 60°C
Cool down time< 20 min
Size150 mm x 100 mm
Mass< 1kg
Mountingany orientation

Physical Layout

Miniature Cryogenic Low Noise Amplifier Physical Layout

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