LAUSR

In this paper, for the first time, a novel compact lumped-element coupler is proposed, which can implement arbitrary power-dividing ratios, arbitrary phase differences, and arbitrary impedance matching. In the design, the proposed coupler is composed of eight lumped LC elements, which achieves a compact circuit size and avoids the complexity of implementation. In the section of circuit analysis, explicit close-formed design equations are derived. For demonstration, three cases of normal couplers and two cases of rat-race couplers extracted from the design procedure are simulated and fabricated. Good agreements between the measurements and simulations verify the design theory of the multifunctional LC coupler.