Size and Periodicity Effects on Terahertz Properties of Gammadion Metamaterials.

We studied the effects on the terahertz transmission of gammadion metamatials by adjusting the size and periodicity of the metamaterial, while keeping the periodicity and size fixed, respectively. The terahertz transmission responses of these metamaterials were analyzed using terahertz time domain spectroscopy as well as finite difference time domain electromagnetic simulations. We have found that increasing size or periodicity results in a red shift of the resonant frequency, and that increasing size or decreasing periodicity results in the formation of a second resonant frequency. We associate these effects with the changing lengths of the microstrip lines that make up the metamaterial, as well as the changing strength of nearest-neighbor coupling between gammadions.