Dual- and Triple-Band Wilkinson Power Dividers Based on Composite Right- and Left-Handed Transmission Lines

This paper presents dual- and triple-band equal-split Wilkinson power dividers (WPDs) based on composite right- and left-handed transmission lines. Good isolation between output ports and impedance matching at input ports are achieved simultaneously at all pass-band frequencies for both dual- and triple-band WPDs. The theoretical closed-form design equations are derived, and the design allows a wide range of flexibility for the allocations of the passbands. To verify the proposed design, two prototypes are fabricated and measurements show good agreement with simulated data. The first design is a triple-band WPD with passbands centered at 0.8, 1.3, and 1.85 GHz, and the second one is a dual-band WPD with passbands centered at 0.7 and 1.5 GHz. The triple-band divider has a length of 0.66 wavelengths in the substrate and is more compact comparing to traditional WPDs. The dual-band power divider is designed to have a wide fractional bandwidth with more than 20% at the lower passband and 41% at the upper passband. Measurements also show a good insertion loss at each input port, which is less than 3.6 dB at the center of each passband.