Microwave active solid state cold/warm noise source
US6137440A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1997 |
| Grant date | Oct 24, 2000 |
| Priority date | — |
| Expiry date | Nov 4, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B5/1852
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A microwave active noise source and method used for calibrating a radiometer includes a transistor configured as a noise equivalent model having a gate port, drain port and source port. During calibration of the radiometer the drain port is terminated and a bias circuit applies DC bias to the noise equivalent model. The bias circuit controls the DC bias such that a hot thermal radiation temperature and a cold thermal radiation temperature are alternately generated at the gate port of the noise equivalent model. A source inductance coupled to the source port of the noise equivalent model provides series feedback. To match the impedances in the noise source, an output matching impedance network is connected to the drain port and an input matching impedance network is connected to the gate port of the noise equivalent model. The input matching impedance network includes an input port for outputting the hot and cold thermal radiation temperatures used to calibrate the radiometer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.