Bandpass-Filtering Coupled-Line Power Divider with Broadband Arbitrary Phase Difference

Abstract

This paper presents an approach for the design of a bandpass-filtering coupled-line power divider with a broadband arbitrary phase difference between two paths. The proposed circuit consists of a Wilkinson power divider and N th-order coupled line bandpass filters(BPFs) having different fractional bandwidths(FBWs). Through control of the FBWs of the N th-order BPFs, a constant phase difference over broadband can be obtained. From the analysis, the design equations of the proposed circuit are derived. To prove the validity of the proposed circuit, a power divider having a phase difference of 180° is designed and fabricated. From the measurement results, the phase and magnitude imbalances are 180°±3.22° and ±0.2 dB, respectively, at the center frequency of 2.90 GHz with an operation bandwidth of 310 MHz.