Improved mm-wave Gunn-mixer receivers
Abstract
The paper shows how additional improvements in the performance of self-oscillating Gunn diode mixers can be obtained by applying automatic frequency control (AFC) using the existing IF to provide the control function. Evidence is presented which indicates that the improvement in conversion gain is a result of the AFC reducing local oscillator FM jitter, thus concentrating into the center frequency of the IF that energy which otherwise would have been distributed among FM jitter sidebands. The improvement described does not require bandwidth reduction. In contrast, the IF amplitude is increased for the same noise rather than the noise bandwidth being reduced for the same IF amplitude. A mathematical analysis is presented both for a simple linearized approximation for the AFC loop and for FM jitter noise reduction with AFC.
- Publication:
-
Microwave Journal
- Pub Date:
- March 1977
- Bibcode:
- 1977MiJo...20...43L
- Keywords:
-
- Automatic Frequency Control;
- Frequency Converters;
- Frequency Response;
- Gunn Diodes;
- Microwave Oscillators;
- Millimeter Waves;
- Self Oscillation;
- Bessel Functions;
- Cost Reduction;
- Microwave Equipment;
- Phase Modulation;
- Signal To Noise Ratios;
- Electronics and Electrical Engineering