A compact two-dimensional phased array using grounded coplanar-waveguides butler matrices

A 2.45 GHz two-dimensional (2-D) 4×4 multi-beam phased array was designed, based on the Butler matrix beamforming technique. Sixteen beam states are produced by two stacks of 4-way Butler matrices, where one stack controls the vertical angle and the other one controls the horizontal angle. To achieve system compactness, the Butler matrix in grounded coplanar-waveguide (CPWG) configuration is newly designed, leading to 54% size reduction comparing with the microstrip line-based Butler matrix. The demonstration of beamforming capability of the integrated array is provided.