Design and Fabrication of a microstrip 4x4 Butler Matrix Operating at 2.59 GHz for 5G Applications

This paper presents the design and fabrication of a microstrip 4x4 Butler Matrix beamforming network operating at 2.59GHz for 5G Applications. The design is implemented on an FR-4 epoxy substrate with dielectric constant of 4.4 and thickness of 0.8mm. This 4x4 Butler Matrix consists of the 90- degree 3-dB Hybrid coupler, crossover coupler, and 45-degree phase shifter that was optimized with circuit simulations, fabricated, and validated prior to integration into a 4x4 Butler Matrix beamforming network. Simulated and measured results show good agreement with theoretical calculations.