A miniaturized ring resonator using a left-handed transmission line section

In this paper, we present a novel miniaturized ring resonator configuration that employs a combination of right-handed and left-handed transmission lines. It is shown that combining right-handed and left-handed transmission lines can result in a miniaturized resonator configuration whose resonant frequency is independent of its length. The proposed concept allows the realization of considerably smaller resonators in comparison with traditional ring resonators. Moreover, it offers a remarkable wide spurious free window. In practice, the maximum miniaturization of the proposed ring resonator is limited by the maximum achievable capacitance and inductance per unit area. The proposed concept can also be extended to other planar resonator configurations. Practical considerations to realize these structures are also discussed.