Novel Synthesizing Technique for Interference Rejection in Future Integrated Base Station

A novel technique minimizing signal loss while enhancing isolation between transmitter and receiver is introduced in this paper by using four-port diplexer topology. Three and four-port networks are intensively analysed and synthesized for solving S-parameter equations. From the analytical solution verified by 3D fullwave simulations, the four-port diplexer can be designed by using two diplexers with 180° different phase. This technique offers the signal isolation of 68.46 dB between transmitter and receiver module, which is the best figure ever reported to date. The four-port network exploits both high and low-Q factor filters for the cost reduction while still offering superior figure-of-merits.