Beam-Wave Interaction Simulation of Rectangular Helix Traveling Wave Tube
The beam-wave interaction of rectangular helix traveling-wave-tube (TWT) is simulated by MAGIC. Two linearly tapered resistance couplers were applied to reduce reflections, which may replace the actual input and output structures and reduce the self-excit
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Beam-Wave Interaction Simulation of Rectangular Helix Traveling Wave Tube Chengfang Fu
Abstract The beam-wave interaction of rectangular helix traveling-wave-tube (TWT) is simulated by MAGIC. Two linearly tapered resistance couplers were applied to reduce reflections, which may replace the actual input and output structures and reduce the self-excitation phenomena. The results show that the computing model is effective to simulate the beam-wave interaction of the rectangular helix TWT. Then some nonlinearly interaction phenomena and parameters of a designed X-band rectangular helix TWT were analyzed, such as the electron bunching, the energy exchange and the output power. And the operating frequency of the designed rectangular helix TWT is from 8 to 12 GHz, the highest output power reaches 480 W, bandwidth is about 4 GHz, and the interaction efficiency is 11.8 %. Keywords High power microwave simulation Particle-in-cell
Rectangular helix TWT Electromagnetic
21.1 Introduction With the rapid development of modern electronic-war and the space applications, the study on the millimeter waves becomes to be a focus [1]. For the reason of size reduction in the millimeter wave band, the size of the slow-wave structures (SWS) become smaller, which makes many efforts have been made to design the innovative interaction structures to meet the new demand of the electric equipments.
C. Fu (&) Huaiyin Institute of Technology, 223003 Huai’an, China e-mail: [email protected]
W. Du (ed.), Informatics and Management Science III, Lecture Notes in Electrical Engineering 206, DOI: 10.1007/978-1-4471-4790-9_21, Springer-Verlag London 2013
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Thus CCR have reported several novel SWSs of this kind, this include the square helix, planar helix and the modified fold waveguide circuits [1]. These circuits can be electroplated directly or photo-litho-graphically printed on a dielectric substrate, which avoids the conventional helix support rod and barrel assembly. Thermal stability is increased since they make contact with the dielectric substrate over an enlarged surface area compared to the conventional SWS. At the same time they are amenable to operation with ribbon beams, which allows increased currents without increased current density [2]. Since the conventional round helix SWS has unique properties, such as wide bandwidth and low dispersion, however, it’s not compatible with MEMS technology. So a related structure in planar geometry was considered [3, 4]. This structure, called the ‘‘Rectangular Helix (RH)’’. The RH is modeled after the conventional round helix, but encompasses a rectangular geometry. In our previous work we have researched the rf characteristics of the RH in free space and in the dielectric using theoretical method [5, 6]. To make up the disadvantage of the theory analysis, the purpose of this paper is to investigate the beam-wave interaction inside the RH TWT using the particle-in-cell (PIC) simulation code MAGIC. MAGIC is one of the outstanding candidates in PIC, so there are many simulatio
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