The Study Of Electromagnetic Properties Of A Novel Single Side Left-handed Metamaterial

As we all known, electromagnetic properties of a kind of material can be characterized by twofundamental physical parameters, the permittivity and the permeability. Left-handed metamaterialsare novel artificial electromagnetic materials that exhibit both negative effective permittivity and thepermeability. So the kinds of materials are widely used in microwave and optical frequencies for itsspecial properties that not found in the natural materials. In the paper, with the software CSTmicrowave studio and the retrieve algorithm, a kind of single sided paired S-ring left-handed materialare studied.1. First, we construct the equivalent circuit for permittivity and the permeability separately of theunit cell of the left-handed material. Then with the use of knowledge of RLC circuit, theeffective permittivity and permeability that describing the relationships between the structuralparameters and the left-handed bandwidth have been derived. Results show that the widths ofthe S-ring and the period sizes of the adjacent unit cell have great impact on the magneticresonance frequency.2. The electromagnetic response, the surface current distribution and the equivalent permittivityand permeability of the left-handed material have been investigated under threeelectromagnetic waves with different orientations of electric field, magnetic field and wavevector. The effective permittivity and permeability are negative in some frequencies, if theelectric resonance and magnetic resonance are strong enough. Results show that the effectivepermittivity and permeability are both negative in the7.43GHz.3. With the simulation, we get the relationships between the left-handed bandwidths and thestructural parameters such as the gaps between the two adjacent S-rings in a unit cell, thewidths of the S-rings, the period sizes of the unit cells in y axis. At last, a left-handedbandwidth of about3.53GHz which is2.6times of the original bandwidth has been obtained.A reasonable change of the structural parameters can effectively affect the bandwidth of thismaterial.4. The loss of the left-handed material is also a great factor that limits its practical application.We analyze how the five factors the thickness of printed circuit board, the permittivity ofprinted circuit board, the dielectric loss tangent of printed circuit board, the thickness of S-ring and the conductivity of S-ring affect the loss of left-handed materials. Among the five factors,the dielectric loss tangent has the greatest impact on the loss of the left-handed material. Whenthe dielectric loss tangent increases to0.4, the permittivity and permeability are positive. So,the left-handed bandwidth disappears.