Research On Broadband And Millimeter Wave Helix Slow-wave Structures

Helix traveling-wave tubes(TWT) with wide-bandwidth, high power, high efficiency and high gain, which especially can be chained with solid state power amplifier(SSPA) and electronic power conditioner(EPC) to form superior Microwave Power Module(MPM), are attractive for many applications, such as radar, aerospace,electronic countermeasures and communication. As the development of the military electronic technology, the helix TWTs with wider bandwidth, higher power, higher frequency, longer life and smaller size are urgent. In this paper, The important works and innovation points are listed below:1. to improve the dispersion characteristics of helix slow-wave structure(SWS), The technique of dispersion shaping is used. With the help of the three-dimensional electromagnetic simulation software HFSS, the helical slow wave structure with Spinal load in the 18-40 GHz band and with T-shaped-vane in the Ka band are designed. To analyze the impact of structural parameters changes in the size on high-frequency characteristics deeply,to get a better high-frequency characteristics.2. The helical slow wave structure with Spinal load is designed by ORION software.it is utilized to run the simulation of beam-wave interaction,Focusing on the impact to beam-wave interaction with different dynamic-velocity tapering(DVT). From our calculations, when the designed beam voltage and beam current are set to be 9.7KV and 0.17 A, respectively, The results show that the output power of fundamental wave ranging from 18 GHz to 40 GHz values are over 180 W, the gain is over 35 dB and the electronic efficiency is over 11%, the gain of second harmonics is lower than-6dB.the corresponding fundamental power and the electronic efficiency have improved greatly with dynamic-velocity tapering(DVT).3. The helical slow wave structure with T-shaped-vane is designed by ORION software. Focusing on the impact to beam-wave interaction with different parameters, Designed a tube with seventy millimeters, the results show that the output power ranging from 26.5 GHz to 40 GHz values are over 55 W, the gain is over 20 dB and the electronic efficiency is over 7%. By further optimization, length becomes sixty millimeters and Electric current becomes 90 mA, the results show that the output power ranging from 26.5 GHz to 40 GHz values are over 54 W, the gain is over 20 dB and the electronic efficiency is over 6.4%.