A Butler Matrix Design for Directional Antenna

This paper demonstrates an 8 X 8 Butler Matrix design that does not employ cross-overs. The Butler Matrix was manufactured on a single side of Printed Circuit Board (PCB) and is intended for use with a low-profile C-band directional antenna array. This solution provides an effective methodology for electronically switching beam states of a planner distributed array where typical applications of active phase shifters would either be cost prohibitive or are unnecessary to meet the technical requirements. This design makes use of a series of quadrature hybrid couplers made up of microstrip line circuit board. Test results show that the Matrix efficiently produces the necessary power and phase distribution to each output port allowing the antenna array to show 8 distinct beam states.