The Coupled Metamaterial Particles Electromagnetic Properties Analysis

In 1968, Veselago postulated the existence of electromagnetic material in which both permittivity and permeability were negative real values, which cause the refractive index to be negative. Such materials are termed as left-handed materials (LHM), which have not received much attention due to their absence in nature until 2000, when the negative refraction has been demonstrated experimentally by using periodic structures containing metallic rods and Split-Ring Resonator(SRR) By Pendry. The successful realization of metamaterials has garnered considerable attentions and discussions all over the world. Some corresponding researches were selected as one of the top ten Research High Lights by Science in 2003 and 2006 respectively.This paper focuses on the electromagnetic properties and applications of the metamaterials. A rigorous analysis of bianisotropic split-ring resonator metamaterials is presented for different electromagnetic field polarization and propagation directions. An alternative physical explanation for SRR resonance band gaps is gained by revealing the fact that imaginary wave number leads to the SRR resonance. And the theoretical calculation formula of resonant frequency is derived, then investigated the coupling behavior of SRR particle through its field and current distribution, then effective permittivity and permeability of SRR array is Retrieved. Finally, A novel microwave sensor based on waveguide loaded with SRR particle is presented.The main contents and conclusions obtained are as follows:In the fist part, the transmission characteristics of metamaterial unit cell were analyzed. An alternative physical explanation for SRR resonance band gaps is gained by revealing the fact that imaginary wave number leads to the SRR resonance, and the theoretical calculation formula of resonant frequency was derived by analyzing the equivalent electrocircuit.In the second part, the behavior of the magnetic resonance frequency, the magnetic field and the currents in the individual and coupled split ring resonators is investigated. Results show that coupling of the SRRs along the E direction results to shift of the magnetic resonance frequency to lower or higher values, depending on the capacitive or inductive nature of the coupling. Strong SRR coupling along propagation direction usually results to splitting of the single SRR resonance into two distinct resonances, associated with peculiar field and current distributions. The SRR periodic structure was analyzed and the effective permittivity and effective permeability were extracted.In the third part, a novel microwave sensor based on waveguide loaded with SRR particle is presented. The performances of the sensor are analyzed based on the full wave electromagnetic simulator CST, and linear relationship between resonate frequency of the sensor and the permittivity of the material is revealed when the gap of SRR is filled with dielectric material. Besides, the effective permittivity and permeability of the SRR array and the waveguide filled with one dimensional SRR particles are simulated. Results show that the effective permeability of the waveguide loaded with one dimensional SRR particles is negative. A single SRR particle also possesses negative permeability when the dielectric loss of its substrate is small or much thicker copper is coated on the substrate.