Design of miniaturized triple-band quarter-wave open-circuit stub based on simplified dual-composite right/left-handed transmission lines

For miniaturization and multi-band application in modern microwave and wireless communication system, this article proposed a miniaturized triple-band quarter-wave open-circuit stub based on the simplified dual-composite right/left-handed transmission line (S-D-CRLH-TL) for the first time. The proposed S-D-CRLH-TL has been analyzed by the full wave simulator, and the simulated results prove that there are three frequency points with phase of -90-degree in the passbands, and this characteristic can be used to design triple-band quadrature microwave components. Then, the proposed novel triple-band quarter-wave open-circuit stub is fabricated and measured, the measured and simulated results are in good agreement, showing that the designed open-circuit stub operating at 2.29GHz, 2.92GHz and 3.89GHz respectively possess insertion loss -21.08dB, -36.4dB and -26.9dB. In comparison with the conventional design operating at 2.29GHz, this novel open-circuit stub not only realizes triple-band, but also has a 31% size reduction, which thanks to the special dispersion characteristics of S-D-CRLH.