Effects of Substrates with Different Dielectric Parameters on Left-Handed Frequency of Left-Handed Materials

Wedge-shaped left-handed materials (LHMs) with split ring resonators and wires structures are fabricated by photolithography and lift-off techniques, and the variation of left-handed frequency induced by substrates with different dielectric parameters is investigated. The Snell refraction experiments of the LHM samples are carried out on an angular resoled microwave spectrometer, and the results indicate that the left-handed frequencies of the LHMs shifted downward from 10.57GHz to 9.74GHz when the dielectric parameters of the LHM substrates increase from 3.7 to 4.8. Moreover, the finite difference time domain method is used to simulate the microwave transmission properties of the left-handed materials with different substrates, and the experimental results are in agreement with the numerical simulation results. In addition, the reason for the shifting of the left-handed frequency of the LHMs is discussed theoretically.