A novel approach of left-handed (LH) structures is introduced to reduce the size of microwave components by combining a loaded coupled transmission lines and complementary split ring resonators (CSRRs). The performance of the loaded part of the proposed model is equal by two cascaded unit elements. The equivalent circuit model and subsequently, the left and right handed transmission frequencies of the proposed structure are presented. A highly miniaturized dual-band branch-line coupler (BLC) is analyzed, designed, tested and proposed by this technique. The size reduction is reported about 75% in analogy with the conventional ones. The measurement results are in good agreement with the theoretical ones.
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