Study of Eigenmodes of Coaxial Resonators Using Coupled-Wave Theory

Abstract

Based on the surface impedance theory (SIT) and the coupled-wave theory (CWT), this paper has established the second-order transmission line equation applicable to coaxial resonators with corrugated inner conductor. By utilizing the equation, the resonant frequency, Q factor and field profiles geometry of the eigenmodes of coaxial resonators can be calculated in view of the mode coupling, and the variables of the slot width and depth in the coupling coefficient can also be applied to calculate their impact on the resonant frequency and Q factor. The numerical results show that, the slot width and depth have significant impact on the resonant frequency, but their effect on Q factor is approximately negligible.

Study and design of a 170GHz coaxial gyrotron cavity

“…Using Green's theorem and the Stokes theorem, one obtains the mode coupling coefficients [4][5] as following: …”

Research on Eigen-Mode of Coaxial Outer Corrugated Resonator

“…For TM mn , under given condition, the surfaces r = R i and r = R o behave as boundaries of perfect conduction [4]. Therefore, the dispersion equation of the coaxial outer corrugated resonator is the same as smooth-wall coaxial resonator [18]…”

“…To research high frequency field in the coaxial outer corrugated resonator, by using (18), mode coupling coefficients is derived. By Green formula…”

“…For cylindrical resonators, the eigen-mode in view of the mode coupling of different fields has been studied in detail [17]. For coaxial inner corrugated resonators, some researches on the eigen-mode have been carried out [18]. But, researches on the eigen-mode of the coaxial outer corrugated resonator have seldom been found.…”