Novel Butler matrix using CPW multi-layer technology

In this paper, a new configuration of a coplanar waveguide (CPW) beamforming 8-port Butler matrix operating at 5.8 GHz is presented. This matrix is based on a novel CPW multilayer directional coupler. The main objective of the proposed coupler is to avoid using crossovers as employed in conventional Butler matrices. To examine the performance of the proposed matrix, an experimental prototype was fabricated and measured, and the obtained results confirm the proposed approach.