A novel multilayer coupler is proposed in this work. With the symmetric traces, the ground plane can be repeated layer by layer. This innovative design achieves vertically stacked coupling without vias or complicated structures. The solution for a set of coupler specifications is non-unique. The designer has the freedom to choose a proper configuration for different applications and fabrication requirements. The design data generated by method of moments provides the guideline for design procedure and tuning. A prototype 3-dB coupler has been simulated and fabricated. The numerical simulation...