A Compact Filtering Power Divider with Wideband Harmonic-Suppressed Ability

This paper presents a novel design of a wideband power divider (PD) with large spurious suppression. By modifying the Wilkinson-PD structure with simple stubs, out-of-band controllable transmission zeros are achieved up to the fifth harmonics. Only a few transmission lines and one resistor are needed. With derived equations for calculating the design parameters, the proposed circuit can be optimized and implemented flexibly at a fast speed. To validate the proposed design, a 1.0 GHz filtering PD prototype is demonstrated on the Rogers RO4003C substrate. The fabricated PD shows a compact layout, occupying only 0.13 lambda(0)x0.18 lambda(0). From the measurement results, 70% operating bandwidth and a 0.2 dB in-band insertion loss are achieved. Meanwhile, the superb spurious control ability is also tested, which shows >= 40 dB ultra- wide harmonic suppression covering 2nd to 5th and >= 23 dB stopband suppression at 1.9 similar to 5.2 GHz.