In this article, tuning is applied to metamaterial transmission lines loaded with complementary split-ring resonators. Specifically, a double-tuning scheme is proposed, where one semiconductor varactor diode is placed between the inner and outer metallic regions of the complementary split-ring resonator, whereas the second varactor diode is placed in series with the host line above the position of the complementary split-ring resonator. By tuning the former varactor, we can tailor the electrical characteristics of the complementary split-ring resonator. By using the second varactor as a switch, we can choose operation of the structure as a left-handed or as a negative permittivity structure. The result is a reconfigurable/tunable filtering structure that can be used as notch filter or narrow band-pass filter. A prototype device has been designed and fabricated.
- Complementary split-ring resonator