TUNABLE SINGLE-NEGATIVE METAMATERIALS BASED ON MICROSTRIP TRANSMISSION LINE WITH VARACTOR DIODES LOADING

In this paper, tunable single-negative (TSNG) metamaterials based on microstrip with varactor diodes loading are investigated. By tuning the external voltage, our structure can provide either an epsilon-negative or a mu-negative band gap, with varying gap width (the ratio of bandwidth to center frequency can be from 0 to over 100%) and depth (from 0 dB to about -30 dB). Moreover, the tunneling mode in a heterostructure constructed by epsilon-negative and TSNG metamaterials is also studied. The results show that its transmission, Q-factor, and electromagnetic localization can also be controlled conveniently. All these properties make our structure promising to be utilized as a practical switching device, or a suitable platform for the study of nonlinear effect in metamaterials.