Metamaterial Filters

Abstract

Filters are one of basic blocks of any communication systems. Filters allow a certain band of frequencies and reject rest of the frequencies. The filters are classified based on the frequency selection. Planar filters are realized using microstrip lines. Microstrip filters are designed using a combination of transmission lines by modifying the alignment of the lines to either couple or reject the selected frequencies. The appropriate equations for design of microstrip line are included. But, these microstrip filters have some disadvantages in getting compact, multiple band and sharp rolls. Metamaterials have properties of negative permittivity and permeability, which can control the electromagnetic wave propagation in the medium. Instead of controlling the wave propagation only through microstrip line coupling, metamaterials are incorporated along the transmission line to control the electromagnetic wave propagation. As the bandpass filter is the widely used filter in the transmitter and receivers in communication systems, the design of metamaterial-based microwave bandpass filters is elaborated. Design of bandpass filter with metamaterial structures with coplanar waveguide transmission line is elaborated. The modifications to be done to the transmission line for obtaining bandpass filter are given. Design of bandpass filter with split ring resonators and complementary split resonators is explained. A dual-bandpass filter design with complementary split ring resonators is also illustrated. Novel metamaterial resonators are represented. The role of the gaps and vias along the microstrip line is also discussed. The simulation results of the designed filters are presented.KeywordsMetamaterialsFrequency responsePassbandStopbandSplit ring resonators