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

In this paper, a compact 7–12 GHz 1-to-4 differential power splitter using broadside-coupled coplanar waveguide (CPW) and substrate-integrated defected ground structure (SIDGS) is proposed, which makes use of the multilayer printed circuit board (PCB) technology. 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 introduced. Such spur-lines can not only achieve low amplitude/phase imbalances, but also extend the upper stopband with low radiation loss. To verify the mechanism mentioned above, a prototype of 1-to-4 differential power splitter is implemented. Good agreement between measured and simulated results is achieved. The measured in-band amplitude/phase imbalances of the 1-to-4 0 degree/180 degree power splitter are ±0.15 dB/±1 degree and ±0.75 dB/±1.5 degree, respectively.