Large Signal Analysis of a New Meander Line Topology for W-band Traveling Wave Tubes

Meander lines are promising slow wave structures (SWSs) for millimeter-wave traveling wave tubes (TWTs) due to low-cost manufacture, low-voltage operation and high interaction impedance. However, experimental results on meander lines are rare in literature. Phase velocity and interaction impedance are the most important parameters for the design and characterization of TWT SWSs. Their experimental determination in meander lines is crucial for validating simulations and developing new topologies. Based on a new theoretical model, this paper presents an experimental procedure to determine the phase velocity and the interaction impedance. The method is validated on four different Ka-band (33-37 GHz) meander line SWSs, including two of a novel topology.

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“…Equation 13and (14) can be derived in a similar fashion applying the interface conditions that correspond to each field component.…”

Section: Appendix a Derivation Of The Parametersmentioning

confidence: 99%

“…Two novel meander lines (NML1 and NML2) are proposed to improve specific performance depending on the application of the TWT. One, NML1, offers flatter dispersion over a wide band [14], the other, NML2, provides higher interaction impedance but over a narrower band [15]. A standard meander line (SML) ( Fig.…”

Section: Introductionmentioning

confidence: 99%

Experimental Validation of Phase Velocity and Interaction Impedance of Meander-Line Slow-Wave Structures for Space Traveling-Wave Tubes

Socuellamos

Dionisio

Letizia

et al. 2021

IEEE Trans. Microwave Theory Techn.

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“…The coupling transition design between the 3D meander and waveguides is similar to the one for planar meanders [6]. The bottom planar meander line is extended at both ends acting as a probe for the electric field coming from and leaving the waveguide (Fig.…”

Section: D Meander Simulationsmentioning

confidence: 99%

“…The use of sheet electron beams as particle sources in traveling wave tubes is not desirable due to the instability that the beam suffers as the electrons travel along the tube [5]. Cylindrical geometries are typically much more stable and can be easily controlled by means of conventional periodic permanent magnets, but the results for gain and output power are very discrete [6]. Even though different efforts have been made in order to increase the output levels using cylindrical electron beams [7,8], the results are not yet satisfactory for satellite applications at W-band and better configurations are necessary.…”

Section: Introductionmentioning

confidence: 99%

3D Meander Line Slow Wave Structure for W-band TWT

Socuellamos

Letizia

Dionisio

et al. 2020

2020 IEEE 21st International Conference on Vacuum Electronics (IVEC)

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Planar meander lines have been recently studied in detail due to their favorable properties as slow wave structures for traveling wave tubes. However, the interaction of a cylindrical electron beam with this kind of structures is not efficient enough in order to achieve the output power levels required for space applications at Wband. A new design, suitable and optimized for the cylindrical beam geometry, is introduced in this work. Cold and large signal results are presented in the paper.

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“…This has made necessary to find alternative slow wave structures for space TWTs [2,3]. Meander lines are theoretically capable of providing similar gain and output power as full-metal SWSs while needing a much lower beam voltage [4,5]. This benefit, along with the suitability for lowcost and high-volume production, makes meander lines a promising SWS for W-band TWT.…”

Section: Introductionmentioning

confidence: 99%