A composite right/left-handed transmission line resonator with 3 unit cells is fabricated and its radiation loss is investigated. At the zeroth order resonance state, the resonator shows radiation loss, which is dominant over other conductor and dielectric losses. This paper investigates the radiation loss of zeroth order resonators from a quality-factor point of view. With the use of a metal shield, the quality factor is considerably increased through a reduction of the radiation loss. The increase in the quality factor is explained by means of the extracted parameters of the equivalent circuit model.
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