High-Q CRLH transmission line stub resonator utilizing negative order resonance modes

A composite right/left-handed transmission line stub resonator utilizing negative-order resonance mode as transmission zeros is presented. The compact resonator sizes 1/3 of conventional half-wavelength stub resonators. We demonstrate that the slow group velocity of the left-handed waves enhances the unloaded-Q of the resonator by a factor of 2 or more. As a result, the loaded-Q, controlled by the left-handed reactive elements, can be arbitrarily increased without incurring significant insertion loss as in the case of conventional right-handed stub resonators. The physical mechanisms of the distinct features are discussed based on measured and simulated results.