A Broadband Power Divider with 90 Degree Phase Shifter

Power dividers and phase shifters play important roles in microwave systems such as base stations, radars and other mobile devices. With the development of various wireless communication systems, the working bandwidth for many mobile terminal devices will be more and more multi-band or broadband. The RF circuits of power dividers and shifters, therefore, should be designed for multi-band or broadband to meet the development of various wireless communication systems. This will cause some problems for the design of power dividers and shifters.In some broadband circular polarization antenna systems, the application of broadband power dividers and shifters as a feeding network can provide a broadband 90 deg phase to realize a good broadband circular polarization property.Based on the system mentioned above, a broadband power divider-shifter for broadband circular polarization antenna system is designed in this paper. For this divider-shifter design, first a multi-section Wilkinson structure is used for a power divider to realize the broadband property. Next, the transmission line loaded with a T-shape open stub structure is used for a phase shifter to realize the broad band similarly.The working frequency of the proposed system covers from 3 to 5.5 GHz, which proves that the system can supply important structure for our further design of broadband circular polarization antenna.