Phase locking of Gunn diodes

• Main Author: Smith, P. C. L.
• Published: University of Surrey 1973
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.473229

Theoretical and experimental investigations have been carried out on injection locked Gunn diodes operating in a microwave cavity at X-band. Particular attention has been paid to the behaviour that occurs when the injected signal level is of the same order of magnitude as the output power of the locked device. The limitations of existing theories of phase-locking are discussed, and a theory is presented which, qualitatively at least, appears to provide a closer description of observed behaviour. The development of this theory involved measurements of active diode admittance, and a detailed examination of the equivalent circuits of the diode package and of the microwave cavity in which the diode was mounted. During the course of this work a simple, but useful, method of evaluating one of the key diode package parameters was developed. The mutual synchronisation of two oscillating diodes has also been investigated experimentally, both for diodes mounted in the same microwave cavity and for diodes in separate cavities coupled through a mutual admittance. In the latter case a theory is presented which shows good agreement with small - signal experimental results.