Novel Design of Miniaturized Filtering Power Dividers Using Dual-Composite Right-/Left-Handed Resonators

One kind of miniaturized filtering power divider (FPD) with a new topology is proposed. For previously published FPDs, the isolation resistors were usually added with additional quarter-wave (λ/4) transmission lines for output isolation. In this paper, λ/4 transmission lines are removed, and the resistor is added to the loaded resonator for the miniaturized design. By regarding the input external quality factor (Qe-in) as an admittance inverter, the indispensable 90° delay can be easily realized. To further improve the miniaturization, the dual-composite right-/left-handed (D-CRLH) resonators are adopted; therefore, the overall sizes of the resulting FPDs can be smaller than 0.012λg2. Moreover, the equivalent circuit of the proposed FPD is investigated for the performance improvement. Input Qe-inshould be double of output Qe-outfor good matching, and good isolation can be obtained by appropriately utilizing Qe-in. For demonstration, three D-CRLH FPDs are designed for narrowband, wideband, and dual-band applications. Satisfactory agreements between the measured results and theoretical expectations are observed, verifying the validity of the proposed design concepts.