Design, Fabrication and Verification of a Millimeter Wave Butler Matrix Antenna

The design, fabrication and verification of a Butler matrix beamforming network connected to a fourantenna element patch array implemented at 26GHz on a four-layer printed circuit board is designed, fabricated and verified. In order to avoid crossover, the chosen solution is designed by using two cascaded 90-degree hybrids, forming a 4-port which gives the high isolation. The results from testing agreed well with simulations, indicating that the chosen circuit design based on a four-layer PCB board made from Rogers RT-duroid 5880, a Butler network design with no crossover and probe fed patches, is robust and well suited for 5G massive MIMO antenna applications covering a bandwidth 1GHz in the 26GHz band.