FM-noise measurements of 94 GHz CW IMPATTs using a quasi-optical resonator
Abstract
A direct detection technique for evaluating the FM-noise of 94 GHz IMPATT diodes is described in which FM-AM conversion is provided by the high-Q of a quasi-optical resonator. A planar millimeter wave Fabry-Perot interferometer consisting of two antennas and two metal plate reflectors with coupling holes is described. The system may be regarded as a resonant cavity formed by the parallel metal plates and the multiple reflections of plane waves between them. For this quasi-optical resonator, a Q-value of more than 30,000 corresponding to a bandwidth of abouta 3 MHz may be easily attained at an operation frequency of 94 GHz. An Impatt oscillator stabilized by high Q can be tuned in a sufficiently wide frequency range and gives very good results as a local oscillator. While results of FM-noise measurements demonstrate that there is no difference between direct detection or heterodyne techniques, direct detection does not require a highly stable local oscillator.
- Publication:
-
Military Microwaves 1982
- Pub Date:
- 1983
- Bibcode:
- 1983mimi.proc..223F
- Keywords:
-
- Amplitude Modulation;
- Avalanche Diodes;
- Frequency Modulation;
- Microwave Oscillators;
- Noise Measurement;
- Optical Resonators;
- Cavity Resonators;
- Fabry-Perot Interferometers;
- Millimeter Waves;
- Optical Heterodyning;
- Phase Locked Systems;
- Electronics and Electrical Engineering