Improved equivalent circuit model of practical coupled‐cavity slow‐wave structures for TWTs

Abstract

ABSTRACT:

Theory, Simulations, and Experiments of the Dispersion and Interaction Impedance for the Double-Slot Coupled-Cavity Slow Wave Structure in TWT

“…6 and 7 show a comparison of the dispersion and the beam on-axis interaction impedance characteristics obtained by cold test ( 's), the proposed theoretical model (×'s), Ansoft HFSS code(solid line), and the equivalent circuit model (dashed line), respectively. The electric parameters in the equivalent circuit, such as the resonant frequency of the cavity and slot, were obtained from the formulas in [7] and [8]. The dispersion obtained by these experiments differs from that obtained by the theoretical model as well as the Ansoft HFSS code by not >0.5%, whereas it differs from the equivalent circuit model by not >3%.…”

“…Besides the high accuracy, there are some other advantages of the theoretical method compared with the equivalent circuit, including: 1) the theoretical model is valid for arbitrary mode and harmonic, whereas the equivalent circuit model requires different formulas to calculate the cavity mode and the slot mode, and the interaction impedance obtained from the circuit model was also based on the field analysis [18], and 2) except the geometric dimensions, other parameters are not required to be adjusted in the theoretical method. Conversely, in the equivalent circuit model, considering the concentration of electric field near the ferrule tips, the formula of the gap capacitance needs to be appropriately modified by adjusting some parameters, which are related to the frequency and geometric dimensions, and has a great effect on the high frequency characteristics [7], [8].…”

“…The matrices Y 10 , Y 30 , Y 11 , and Y 31 are relevant to ψ, which is defined as the staggered angle between two adjacent walls and ranging from 0 • to 90 • for a double-slot CCSWS. Then, by changing ϕ from 0 to π, the dispersion relation can be obtained by solving (8). Let us take the following sets of basic functions into consideration [15], [16]:…”

Characterization of a Ka-band Sheet-Beam Coupled-Cavity Slow-Wave Structure

“…To help understand the dispersive behavior of the structure, we can determine the resonance frequencies associated with different parts of the structure using simple analytical models similar to those of Curnow [8], Carter and Shunkang [9], and Christie et al [10]. Using the dimensions in Table I and the dispersion diagram of Fig.…”

Design and Simulation of Inductively loaded Inter-digital SWS

“…The same structure also was simulated using NIAFIA by giving two different runs in the eigen mode solver, one with magnetic and the other with electric boundary conditions at both ends and the frequencies corresponding to 7i to 27i in steps of 0.125 7i are obtained. The post processor section of MAFIA was used to compute the total impedance [4] directly.…”