STUDY ON MICROWAVE EXCITED BY VIRTUAL CATHODE OSCILLATION IN CAVITY

Microwave excited by virtual cathode (VC) oscillation in a cylindrical cavity is analyzed. The VC is regarded as a oscillating charged disk. By the means of model expansion method, the relation between microwav e frequency and VC oscillation in a specific cylindrical cavity is obt ained. The expressions of mode expansion coefficients are derived. The results show that at longer cavity length, the microwave excited is m ore pure, this is in good agreement with experiment results. Analysis confirms that the closer is the characteristic frequency of a mode to the oscillating frequency of VC, the larger is the mode expansion coef ficient.