Novel Electromagnetic Radiation Based On Double-negative Metamaterials

Double-negative metamaterial (DNM) is a new kind of artificial electromagneticmaterial with both effective negative real parts of permittivity and permeability. It hasmany unique properties different from normal materials, such as negative refraction,reverse Doppler effect, reversed Cherenkov radiation effect and so on. The firstexperimental research achievements of DNM were published in Science magazine inthe year2001. The unit cell of the DNM is composed of split ring resonator and metallicstrip printed on each side of a dielectric substrate. Since then, this kind of artificialelectromagnetic material has attracted great interests of reserchers all over the world andbecomes one of the hot topics in worldwide researching. DNM has potentialapplications in many aspects, such as the DNM antenna, filter, directional coupler andso on.Cherenkov radiation is a kind of electromagnetic shock waves excited by chargedparticles moving in some media faster than light in this media. Since the radiation wasdiscovered in1934, it has been broadly used as particle detectors in scientificexperimental researching. Reversed Cherenkov radiation occurs in the media of DNM,and it belongs to a new type of electromagnetic radiation based on DNM. This paperintroduces the design, parameter retrieval and simulation of DNM partially filled incircular waveguide which can be the foundations for the researching of reversedCherenkov radiation. In addition, the preliminary results of radiation excited by sheetelectron beam bunch base on numerical calculation are presented. This physicalmechanism may be applied to develop a new type of high-power, compact THzradiation source.This paper is organized as follows:The first chapter, the basic concept, design method, research status andapplications of DNM as well as a new type electromagnetic radiation based on DNMare described.The second chapter, a method of electromagnetic parameters extraction of DNMbased on Kramers-Kronig Relations is presented, and the electromagnetic parameters of a designated unit cell of DNM has been retrieved by the method.The third chapter, the electromagnetic properties of a circular waveguide partiallyfilled with DNM which is designated as isotropic Lorentz and Drude models aresimulated in the CST Microwave Studio environment, and the simulation on the circularwaveguide partially loaded with real stucture DNMs suitable forTM01mode ispresented based on the above results. They provide the foundation for reseach on furtherverification of reversed Cerenkov radiation in circular waveguide partially loaded withDNMs.The fourth Chapter, a new theoretical model to realize high power radiation basedon a sheet electron beam bunch moving above the semi-infinite isotropic DNMs isintroduced, and a detailed numerical analysis of the method to enhance the radiation byadjusting the parameters of the electron beam and the DNM is presented.The fifth Chapter, the conclusion of the paper, existing problems are summarizedand the future work is indicated.