Recently completed a design of a planar X-band Wilkinson 5-way power splitter.
The planar design is really an approximation of the true Wilkinson design, since for a split of more than two, the true symmetrical Wilkinson split requires a third dimension to route all of the traces and isolation resistors. In simplifying the design, we lose some of the isolation between the split ports, creating a need to weigh the advantages and disadvantages of such a design.
Once the design approach has been determined, the next step is to lay out the geometry. The planar approach deviates from the textbook in order to achieve layout simplicity and cost reduction in a two-layer PCB design. Therefore, since we will be relying heavily on the optimizer, it is particularly important to lay out the geometry in a parametric manner.
In the end the design performed well over a fairly narrow bandwidth (~5%). Critical design parameters included amplitude and phase balance between the lines.
ARSI 