System applications of planar couplers

In this paper, we present the system applications of planar couplers. A uni-planar 3dB 180° coupler with fully symmetrically allocated input and output ports is designed for this purpose. Different from the conventional rat-race coupler, it integrates a compact crossover with a modified conventional coupler to rearrange the Σ, Δ, coupling, and through ports of the 180° coupler. The full-wave electromagnetic simulations are performed and an experimental prototype is fabricated to demonstrate the novel design concept. The measurement results match well with the theoretical and numerical results.