Beamforming networks using cascaded Butler Matrices

Abstract

This paper describes a smart antenna system, which employs the advantages of cascaded Butler Matrices in wireless communication system. By using the narrow beams available from the first Butler Matrix, it is possible for a receiver to increase the gain in the desired signal directions and reduce the gain in interference directions. Hence, high-gain narrow beam signals for long-range application are produced. A technique is introduced which uses a second Butler Matrix, acting as a mirror of the first Butler Matrix, reconstructing the antenna patterns of the individual radiating elements. The resulting outputs have broad beam width that can be used for short-range communication. This beamforming network using Butler Matrices provides a method, which could be applicable in wireless communication system applications.