Miniaturized 7–12GHz 1-to-4 Differential Power Splitter with Low Amplitude/Phase Imbalances Using Broadside-Coupled CPW/SIDGS Scheme and Embedded CPW Spur-Line

In this paper, a compact 7–12 GHz 1-to-4 differential power splitter is proposed using the broadside-coupled coplanar waveguide (CPW) and substrate-integrated defected ground structure (SIDGS). The hybrid CPW/SIDGS scheme introduces 1-to-4 differential power splitter response. Meanwhile, the CPW spur-lines embedded at the input/output ports and broadside-coupled CPW/SIDGS are developed. Such spur-lines can not only achieve low amplitude/phase imbalances, but also extend the upper stopband with low radiation loss. Then, to verify the mechanism mentioned above, a prototype of 1-to-4 differential power splitter is proposed and fabricated. Good agreement between measured and simulated results is achieved. The measured in-band amplitude/phase imbalances of the 1-to-4 0°/180° power splitter are ±0.15 dB/±1° and ±0.75 dB/±1.5°, respectively.