Abstract
This paper proposes an easy-to-design, theory-consistent compact feeding circuit, with a single input and four outputs, being comprised of two hybrid circuits that are capable of switching a beam in three directions. The circuits that determine the phase differences between the antennas are present on the same single layer, and thus there is no effect of vias and the design agrees well with the underlying theory. In addition, the vertically and horizontally symmetrical circuit pattern contributes to a substantial reduction in design time. The circuit is designed for use in the ISM band and its properties are evaluated using an RF circuit simulator. A prototype is fabricated and evaluated. The results of the simulation and measurement agree well with the theoretical values. The dimensions of the feeding circuit are 75(H) × 55(W) × 3.0(T)mm.
