Analysis and design of wideband active power splitter with interleaf transmission line topology

This article proposes a new wideband active power splitter design where the gain cells along the input transmission line are arranged in interleaf rather than the conventional parallel style, thus the circuit's high-frequency performance can be greatly improved. Both theoretical analysis and circuit simulation have been carried out; as a demonstration, parallel and interleaf active power splitters are designed using 0.1 mu m GaAs pseudo-morphic heterostructure field effect transistors (GaAs pHEMT) process and measured on-wafer. The results clearly indicate the superiority of the interleaf topology. A 40 GHz interleaf active power splitter in 90 nm complementary metal-oxide-semiconductor (CMOS) is then presented where the magnitude and phase imbalance between the two output ports are 0.15 dB and 2.6 degrees at 20 GHz, and 0.16 dB and 14 degrees at 40 GHz. The output-port isolation is better than 30 dB across the whole frequency range.