Mode Composite Coplanar Waveguide Duplexing Power Divider with Large Frequency Ratio for 5G Multiband System Application

This paper proposes a duplexing power divider (DPD) with a large frequency ratio based on the mode composite coplanar waveguide (MCCPW). The DPD is a five-port network circuit. It integrates the function of the duplexer and power divider within a compact size. The overall DPD can be regarded as a combination of two filtering power dividers and a frequency splitter. The low-band channel circuit is a filtering power divider with harmonic suppression, the bandwidth ranges from 2 GHz to 6 GHz, covering some of the typical frequencies (2.4 GHz, 3.5 GHz, and 5.8 GHz) in sub-6 GHz. The high-frequency band filtering power divider works in substrate integrated waveguide (SIW)-TE10 mode. The bandwidth ranges from 27 GHz to 29 GHz targeting 5G millimeter wave application. The two bands of the duplexer can be designed independently with very high freedom due to the mode separation used in the MCCPW. The DPD can be fabricated using a single PCB process and assembled by the fixing screws. The measured results of the DPD have good agreement with its simulation. The MCCPW-based DPD has the benefits of multi-function, large frequency ratio, high design freedom, high isolation, and high mid-band suppression at the same time with compact size. It is a promising candidate in the multiband system with large frequency ratios such as 5G.