Analysis of Ridge-Loaded Folded-Waveguide Slow-Wave Structures for Broadband Traveling-Wave Tubes

Abstract

Abstract-An E-plane serpentine folded-waveguide slow-wave structure with ridge loading on one of its broad walls is proposed for broadband traveling-wave tubes (TWTs) and studied using a simple quasi-transverse-electromagnetic analysis for the dispersion and interaction impedance characteristics, including the effects of the beam-hole discontinuity. The results are validated against cold test measurements, an approximate transmission-line parametric analysis, an equivalent circuit analysis, and 3-D electromagnetic modeling using CST Microwave Studio. The effect of the structure parameters on widening the bandwidth of a TWT is also studied.Index Terms-Broadbanding, equivalent circuit analysis, folded-waveguide slow-wave structure (SWS), quasi-transverseelectromagnetic (quasi-TEM) analysis, ridge loading.

Equivalent Circuit Analysis of Ridge-Loaded Folded-Waveguide Slow-Wave Structures for Millimeter-Wave Traveling-Wave Tubes

“…We can obtain the dispersion relation by solving the Equations (16)- (18). The effective phase shift per period of the structure, as seen by the electron beam, is given by…”

“…With respect to the equivalent circuit, some scholars have paid attention to it, such as Booske et al [12], Liu [15], Na et al [16], Han et al [17] and Sumathy et al [18]. Na et al [16] and Han et al [17] exclude the effect of the beam hole.…”

“…A thorough equivalent circuit analysis of folded-waveguide slow-wave structure including the effect of the beam hole was proposed by Booske et al [12]. By means of the high pass filter model, the analysis of the high-frequency characteristic of FWG-SWS has been developed by Sumathy et al [18].…”

Nose-cone loaded folded-waveguide delay lines for Q-band traveling-wave tubes

“…Transverse [2] and longitudinal ridges [3] as well as metamaterial insertions [4] have been proposed to shape the electric field for enhanced beamwave coupling. However, the bandwidth is highly reduced by these modifications.…”

Analytical Exploration of Folded Waveguide Circuit Design for High-power Traveling-wave Tube Amplifier

“…The accuracy of these formulas is adequate for cold-cavity design in the early stage. Refined analysis can be conducted further following the approaches adopted in [9][10][11]. We begin with an analysis of the dispersion features of the FWSWS.…”