US Patent 11336028 Butler-based quasi-omni MIMO antenna

An omnidirectional MIMO antenna system includes a multi-panel antenna, each panel including a plurality of antenna elements and a plurality of beam forming networks employing Butler matrices. Each Butler matrix has the same number of input ports and output ports. The total number of the input ports of the Butler matrices is equal to the number of ports of the MIMO antenna, each of the input ports receiving the same signal. Each of the output ports of each of the Butler matrices is coupled to an antenna element within the plurality of the antenna elements, such that the multi-panel antenna exhibits a quasi-omnidirectional beam pattern.