Design of 4x4 Butler Matrix for Beamforming 5G Antenna

Butler matrix is one of the most frequently used beamforming techniques for 5G antenna development. In this paper, a 4x4 butler matrix integrated with a 5G antenna is designed. The array antenna works at 38 GHz. The antenna has the ability to transmit signals in various directions. The simulated results of the butler matrix show the phase difference of P1 and P4 in -45° with a phase unbalanced of 15°, and P2 and P3 have a phase unbalanced of 48°. The main beams directions of the antenna are $8^{\circ},-26^{\circ},26^{\circ}$, and -8° respectively. The beamforming antenna works well with the butler matrix.