Synthesis of Wideband Filtering Couplers for Arbitrary High Power-Division Ratios Based on Three Different Types of Coupled-Line Sections
Yana Zheng, Weimin Wang, Yongle Wu
Abstract
In this brief, for the first time, a novel wideband coupled-line filtering coupler for arbitrary high power-division ratios is proposed. By utilizing three different types of λ/4 coupled-line sections, the coupler can be applied in arbitrary high power-division ratios without using extra equivalent circuits, while the coupler has the advantages of wideband, high frequency selectivity, and inherent DC-blocking. For demonstration, a 15-dB wideband coupled-line filtering coupler operating at 3.5 GHz is designed, simulated, and fabricated. The measured fractional bandwidths for | S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> |, isolation, phase and amplitude imbalance conditions are 61.1%, 111.25%, 62.54%, and 53.48% respectively, which are in good agreement with the simulated results.