1. Design considerations for high-Q bandpass microwave oscillator sensors based upon resonant amplification
- Author
-
John S. McCloy, A. Mark Jones, James F. Kelly, and Jonathan R. Tedeschi
- Subjects
Physics ,Resonator ,Physics and Astronomy (miscellaneous) ,Band-pass filter ,business.industry ,Q factor ,Optoelectronics ,Feedback loop ,business ,Electromagnetic interference ,Microwave ,Positive feedback ,Group delay and phase delay - Abstract
A series of microwave resonant oscillator sensors were designed and characterized using bandpass planar and volumetric electrical resonators having loaded quality factor (Q) values in the range of 2 to 20. The use of these resonators in positive feedback circuits yielded sensor Q-factors of up to 2 × 107, demonstrating Q-factor amplifications on the order of 106. It is shown that the Q-factor amplification can be increased in a positive feedback system through the selection of feedback loop group delay, allowing use of resonators with lower static, loaded Q-factor values. A low-frequency electromagnetic interference sensing application is demonstrated for two resonant oscillator configurations, showing considerable frequency sensitivity to 45 kHz emitters.
- Published
- 2014