Design of triband wilkinson power divider using Extended T-shaped stubs

A modified unequal Wilkinson power divider (WPD) with triband operation is presented in this paper. For triband operation, the quarter wave branch lines in the conventional WPD are replaced with extended T-shaped open or short stubs. In the proposed structure, the operating frequencies can be flexibly controlled, provided the second frequency is the mean of the first and third frequencies. The design equations for the structure and the design procedures are well explained in this paper. A sample prototype with the power dividing ratio of 2:1 and operating frequencies of 1.3, 3.0 and 4.7 GHz has been designed, measured and compared. The microstrip circuit with substrate thickness (h) of 0.813 mm and dielectric constant (□_r) of 3.55 is analyzed using AWR software. The frequency response characteristic in terms of return loss reveals that the short stub design gives a better performance in comparison with the open stub design.