Technical information:
| Central frequency |
11.2 GHz |
| Bandwidth |
1.2 GHz |
| Bandpass Filter |
10.7 - 11.9 GHz |
| Front end amplifier |
ξεντ |
| Physical temperature |
15 K |
| System noise temperature |
66 K |
Realized sensitivity
(  = 1 s ) |
3 mK |
| Design |
Switching Radiometer |
| Operating modes |
Double - beam switching
or
Single - beam mode with
a cooled reference |
| Polarization |
No |
| Feed Horn |
Quasi Scalar |
| Calibration |
Noise generator |
Simplified block-diagram of the radiometer
- PF1, PF2 - input feed horns,
- DC1, DC2 - directional couplers,
- S1, S2 - latching circulator switches,
- CI - cooled ferrite isolator,
- GM - p-i-n diode gain modulator,
- BPF - band-pass filter,
- D - square law detector,
- NG1 - noise generator for calibration,
- NG2 - balance noise generator,
- A1 - noise power control attenuator,
- LFA - low frequency amplifier.
Operating modes:
1. For double-beam mode of operation both latching circulator S1
and S2 are switched in phase. The input feed horns H1 and H2 are
connected alternatelly to HEMT amplifier.
2. For single-beam mode latching circulators S1 and S2 are switched in antiphase.
The cooled matched load operates as a reference.
The balance is realized by means of noise adding to the matched load.
Interior of the 15 K cryostat:
- 1 - cooled modulators ( latching circulator switches ),
- 2, 8 - thin-wall thermo-insulating waveguides,
- 3 - waveguide ferrite isolator,
- 4 - waveguide-to-coaxial adapter,
- 5 - HEMT amplifier,
- 6 - output coaxial ferrite isolator,
- 7 - cooled matched load,
- 9 - anti-radiating shield,
|
= 2.7 cm