Photonic Crystal Class Tortuous Waveguide Slow-wave Circuit

The research on photonic crystals has become a hot topic in the world since the concept of photonic crystals has been proposed in the 1980s, and the application research of the photonic crystals is brilliant and fruitful. Photonic crystals are a kind of novel artificial material with special electromagnetic response characteristics. The basic characteristic is photonic band gap (PBG).Because can't be machined automatically, the cost of traveling wave tubes (TWTs) is very high, and the products are not completely consistent, so does the reliability. Further more, the transit of electrons becomes more difficult in TWTs when operating frequency is high. High cost and problem of electron transit extensively limit the application range and the development of TWTs. The solutions of electron transit inside high frequency band only base on new mechanism of electromagnetic wave propagation. Photonic crystals bring new possibility of decreasing cost, resolving problem of electron transit and improving products consistent.The theme of this dissertation is photonic crystal slow-wave structure. Photonic crystals have the capability of reflecting and filtering the electromagnetic waves. If photonic crystal slow-wave structure is designed properly, the desired modes can be bounded in the slow-wave structure, while the undesired modes can radiate out of the slow-wave structure. In comparison with the slow-wave structure enveloped by metal, the modes in the photonic slow-wave structure are greatly reduced and the stability of the traveling-wave tube can be increased.In this dissertation, firstly, the background of research and present applications of photonic crystals is briefly introduced; the significance and the researching scope of this dissertation are presented first. Based on plane wave expansion method, the intrinsic equations of E mode and H mode of infinite two dimensional photonic crystals are deduced.Secondly, Because of the limitation of analytical methods, a new photonic crystal band gap simulation method using the high frequency simulation software CST MWS is introduced. Then, the high frequency simulation software CST-MWS is applied to analyze the crystal band gaps and the influence of structure parameters on the band gaps. Considered that the entire actual devices are finite, the modes of finite metallic photonic crystals are discussed.Finally, the basic principle of photonic crystal slow-wave structure is discussed and the photonic crystal folded waveguide slow-wave structure is put forward. Then, the photonic crystal folded wave guide slow-wave structure using the first photonic crystal band gap of E mode is investigated, and the effects of structure parameters on the dispersion characteristic and interaction impedance are analyzed. The photonic crystal folded waveguide slow-wave structure using the second photonic crystal band gap of E mode is also investigated. Paper presented here can provide a reference for the study of photonic crystal slow-wave structure.