Multi-section broadband couplers with arbitrary phase differences and power-dividing ratios

Multi-section broadband couplers with arbitrary phase differences and arbitrary power-dividing ratios are presented. By using the even- and odd-mode analysis, the closed-form design equations are derived and then used to determine the circuit parameters of the proposed couplers. Furtherly, the corresponding performance analysis in terms of the bandwidth requirement is provided. Finally, the design procedure of the proposed general couplers is presented. For verification, several couplers with different phase differences and power-dividing ratios are designed, fabricated and measured. The measured results agree well with the simulated results.