A Novel Design Method for Unequal Coupled Line Dual-Band Wilkinson Power Divider

In this article, a new design approach for an unequal coupled transmission line dual-band Wilkinson power divider is presented. A parallel short or open circuit stub is considered at the input port for dual frequency response, and two resistors are connected in order to isolate the outputs. The method is based on an even-odd mode procedure. The main objective of this paper is to fabricate a dual band Wilkinson power divider in order to achieve higher dividing ratio, simple structure, and easier fabrication. First, the desired power divider is divided to two parts known as even and odd mode equivalent circuits. Then by analyzing the circuits, the characteristic impedances are calculated. Next, the coupled transmission lines dimensions are extracted. Afterward by using the calculated characteristic impedances, an error function is formulated, and by minimizing, the isolating resistors are obtained. To clarify the applicability of this method, several microstrip power dividers which operate at both 1 GHz and 2.3 GHz with dividing ratio equal to 1.2589 are designed and simulated with the assumption that relative permittivity is equal to 2.56. In order to demonstration the advantage of using coupled lines tow dividers, one by separated-lines and the other one by coupled-lines are designed and compared with each other. The results illustrate that while the coupled-line dividers have simpler structure, they have significantly similar frequency operation to separated-line ones. Then the designed structure fabricated on an FR4 substrate and S parameters are measured. The results show excellent agreement with simulation. © 2023, Electromagnetics Academy. All rights reserved.