Eigenmodes and Ohmic quality factor of a tapered cavity resonator

In the present communication, authors analyzed eigen-frequency and ohmic quality factor of cylindrical cavity resonator, operating in azimuthally symmetrical mode (TE₀₃), for potential application in gyrotron oscillators. Eigen-frequency and ohmic quality factor has been calculated analytically, the results have been validated with the results obtained from MAGIC simulation software. Ohmic quality factor obtained for tapered cavity have been used to study the effect of structure dimensions like length of mid-section of the cavity, input taper angle and output taper angle. It is found that the ohmic quality factor increases with decrease of the length of mid-section and input taper angle, and with the increase of output taper angle. Out of input and output taper angles, the later was found more sensitive controlling parameter for the ohmic quality factor as well as for ohmic wall losses. Furthermore, the vector fields have been plotted for the mid-section of the cavity to help achieve optimum device operation.