W-band Folded Waveguide Slow-wave Structure

Micro-vacuum electron devices (μVED) have been experiencing tremendous growth in recent years and become one of the most attractive research areas in vacuum electronics. As an example, impressive achievements in growing research of novel interaction circuits used in μVED were gained. μVED combines the mechanism of vacuum electron devices and the advantages of micro-fabrication technology, therefore it can not only operate at high frequency and high power in a wider temperature range, as well as in high radiation environments, but also offer precise, low-cost, high-repeatability miniature circuit to meet the tight tolerances for high frequency devices. Folded waveguide slow wave structure (FWG SWS) has many advantages, such as metallic structure, easy fabrication, high-power handling capability, and moderate bandwidth in high frequency, which has motivated an investigation of folded waveguide traveling wave tube (FWG TWT) as a compact coherent source for the millimeter wave and sub-millimeter wave. According to the emerging applications in military electronic equipment, radar system, communication, investigation of W-band FWG TWT plays an important role in the development of the novel device in this band.This dissertation is concerned with the W-band FWG SWS and related contents, which includes theoretic analysis, preliminary design, numerical simulation and preliminary experiment to lay a foundation for research and development of micro-FWG TWT using micro-fabrication technologies. The contents are as follows:Devious development and current trend of microwave vacuum electron devices were first presented with emphasis on μVED and field emission array (FEA) cathode, of which history and current status were summarized in detail. Then based on requirements for many applications, together with frequency exploitation and the advantages of FWG SWS over other traditional SWSs in millimeter wave, the importance of investigation of W-band was described.