Wideband Four-Way Filtering-Response Power Divider With Improved Output Isolation Based on Coupled Lines

A planar 4-way power divider with bandpass filtering response based on the coupled line is presented. Its frequency response is similar to a coupled line filter. Moreover, open stubs are utilized to get good frequency selectivity by introducing transmission zeros and improve input match. Three isolation resistors are used to satisfy both transmission and isolation property. The equivalent even- and odd-mode circuits of the power divider are analyzed, while the design equations are derived. Comparison of the measured and simulated results is presented to verify the theoretical predications.