A New Miniaturized Broadband Multiway and Polyphase Differential Phase Shifter on Single-Layer PCB Substrate

A new technique to realize miniaturized broadband multiway and polyphase differential phase shifters is proposed and studied in this article. In contrast to existing designs based on coupled-line and loaded stubs, the multiway phase dispersions are controlled by susceptances of multiple resonant tanks in this work, which can well enlarge the operation bandwidth (BW) and avoid the unachievable physical sizes in strip width and coupling gap over a large phase shift range on the universal reference line topology. In addition, its phase-shift range can be highly extended by properly allocating resonant frequencies of resonant tanks in each path to be specified different values. The theoretical analysis and design formula are studied, and the synthesis method is presented to determine all circuit parameters. By virtue of the quasi-lumped element technology, the proposed multiway phase shifter can be flexibly implemented on a single-layer printed circuit board (PCB) substrate with a very compact size. For demonstration, a five-way differential phase shifter in 0°–180° range has been designed, fabricated, and tested. Over a BW of 80.4%, the achieved phase shifts are 45° ± 4°, 90° ± 5°, 135° ± 5°, and 180° ± 6.3° with low insertion loss (IL) (<1.05 dB) and small amplitude imbalance (<0.29 dB). To the best of our knowledge, this is the tested widest multiway differential phase shifter in the 0°–180° range up until now. Meanwhile, the whole circuit size, including the substrate, is less than
$0.30\lambda _{g} \times 0.26\lambda _{g}$
.