Different To The Transmission Line Theory And Research

Metamaterial is one of the frontiers of Physics and Electromagnetism currently, which is a kind of artificial material with simultaneously negative permittivity and permeability. It has many special characters different from normal materials, such as negative refraction, inverse Doppler effect, inverse Cerenkov radiation, anti-paralled phase and group velocities, and so on. There are two methods to realize metamaterial at present: the first is (ROD) and split ring resonators (SRR) array and the other is based on transmission line. One dimension metamaterial is also called left-handed transmission line, which will be most probably used in microwave application because the most of proposed metamaterial are based on left-handed transmission line. In this paper, some special characters of metamaterial are analyzed and the realization of metamaterial are mainly focused on. Based on above analysis, a new type of left-handed transmission line based on waveguide is proposed, and then the application of it is discussed.The basic theory of metamaterial is this thesis' research foundation and we mainly focus on one dimension structure for its broad application. According to the basic theory, negative effective permittivity and permeability can be got in certain frequency band by adding serial capacitance and parallel inductance on normal transmission line periodically. To avoid high loss on microstripline, we propose a new closed and all-mental structure based on coaxial waveguide. Then we get its left-handed passband by HFSS simulation and use equivalent circuit theory to testify its coherence.Because of the special characters of metamaterial, it will be got wide application in microwave circuit. Finally, we make use of the proposed structure to design a bandpass filter by optimizing and improving the structure. The advantage of the filter is small in size, simple structure and lower loss. Simulation result of the filter parameter also proves its rationality.