_{1}

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Short wire pairs are simple metamaterial structures. This structure includes a dielectric substrate with metal strips on both sides, of which the electric and magnetic resonant frequencies can be controlled by adjusting the length of the metallic wires. However, to vary the magnetic resonant frequency requires a change in the length of the strip and another patterned photomask. In this investigation, a simple method is introduced that requires only one patterned photomask by shifting the position of faced wire pairs up and down.

A left-handed material (LHM) was demonstrated by D. R. Smith et al. [_{r}, and an array of conducting continuous wires for achieving a negative effective permittivity ε_{r}, the simultaneous combination of which had never before been observed in any previously known material.

One type of metamaterials, referred to as short wire pairs, has a very simple structure [_{r} and μ_{r} were observed at the same frequency of 14 GHz, leading to a negative refractive index. However, to vary the magnetic resonant frequency requires a change in the length of the metal strip and thus another patterned photomask.

We propose a simpler method and structure that requires only one pattern photomask, even if the magnetic resonant frequency is to be changed.

To evaluate the characteristics of short wire pairs, the structures were inserted into a metallic wave guide parallel to each other and the S parameters were measured. The effective μ_{r} can be calculated using the S parameters [_{r} and μ_{r}, the resonant frequencies are accurate and can be easily calculated.

After obtaining S_{11} and S_{21} under conditions of, the complex effective ε_{r} and μ_{r} are given by:

where, and d, ω, and c represent the thickness of the metamaterial unit cell, the angular frequency and the velocity of light in free space, respectively.

The details of the metamaterial used for the calculation model are shown in

where is the real part of complex permeability and is the imaginary part. is changed significantly from a positive value to a negative value around the resonant frequency. On the other hand, peaks at the resonant frequency and is very small at frequencies distant from the resonant frequency.

The S parameters of the short wire pair metamaterial in a metallic waveguide connected to a HP-8510B network analyzer were measured using a coaxial-waveguide converter. The metamaterial sample is shown in

The length of the short wire pairs, was changed to 7

mm in