Design of dual‐band transmission line with flexible phase shifts and its applications.

A novel dual‐band transmission line with flexible phase shifts is presented. To realise dual‐band operations, the proposed transmission line is constructed by series‐connected coupled lines and open‐ended stubs. Using this structure, flexible characteristic impedances and electrical lengths can be designed to operate at two frequencies. Moreover, the proposed dual‐band transmission line features a wide range of realisable frequency ratios and a flexible structure. For practical applications, a planar dual‐band 3 dB branch‐line coupler operating at 2/5.2 GHz is designed using the proposed dual‐band transmission line. The simulation and measurement results agree very well with the design theory. [ABSTRACT FROM AUTHOR]