Callisto has many years experience producing very low noise cryogenic amplifiers for satellite ground stations. The first generation products were aimed at ultimate low noise performance, which is required for Deep Space satellite missions.
Callisto are now able to offer compact cryogenic low noise amplifiers, which can be used in the wider field of satellite communications, particularly in the remote sensing band of 8.0 to 8.4 GHz. The benefit of using a cryogenic LNA, in system terms, is that a smaller diameter antenna can be used to achieve the required G/T performance compared to a system with a conventional un-cooled LNA.
Description
The LNA has a very low noise temperature due to the fact that it uses HEMT amplification devices cooled to very low temperature by a cryogenic refrigerator. The amplification is in two stages; a cryogenic amplifier followed by an ambient temperature post amplifier to give an overall gain of 45 dB or greater.
Cooling of the amplifier to very low temperatures is achieved using a Stirling cycle cryo-cooler. This is a high efficiency refrigerator which has been developed to serve various applications including antenna mast-head filter cooling for Mobile Telephone base stations.
Unlike the older G-M cycle cryo-coolers, the Stirling cycle machines are compact, with the compressor and the refrigerator head integrated into a single assembly. The bearings and seals of these refrigerators are designed for long operating life without the need for periodic service.
The LNA system comprises the LNA assembly and a separate 19” rack mount unit, which houses the power supplies and monitor & control functions.
Outline RF Specifications
| Parameter | Specification |
| Frequency Range | 8.0 – 9.0 GHz |
| Overall gain | > 45dB |
| Noise Temperature | 25 K |
| Input Interface | WR112 W/G |
| Output Interface | SMA |
| Input VSWR | 1.5:1 |
| Output VSWR | 2.0:1 |
| Output Power handling 1dB CP | +5dBm |
Outline Interface Specifications
| Parameter | Specification |
| Environment temperature | 0 - 50°C |
| Thermometry | to monitor LNA temperature and ambient temperature |
| Cool down time | < 2 hours |
| Routine service period | > 3 years under continuous operation |
| Size | 422 mm x 322 mm x 226 mm |
| Mass | <15kg |
| Mounting | any orientation on movable antenna structure |
Learn More about:
- Cryogenic Low Noise Amplifiers
- Noise Measurement Equipment
- Control Software Development
- Waveguide Vacuum/Pressure Windows
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