Fifth generation (5G) wireless communication is next major phase of mobile communications standards beyond the current LTE-Advanced. In order to meet 5G faster speed (1-10 Gbps), millimeter wave frequency band has been recommended for 5G wireless communication. Ka band has been targeted for short-range, high data rate communication. One major challenge in implementation of 29 GHz wireless communication is high path loss and to overcome this limitation, a high gain network is needed. Microstrip based networks are lossy at such high frequency and can’t handle high power. Waveguide based networks are appropriate in Ka band because of low loss, high power handling capability, and reliability.
Due to the 5G demand for high data rate communication and treasure frequency bandwidth, phased array systems are found significant in wireless communications. Depending on the operating environment, phased arrays can adapt their radiation patterns as well as cancel out information in unwanted directions. Mobile communications networks use MIMO technology to achieve high data rates. In an FD-MIMO (Full Dimension MIMO) system, as shown in fig. 1, a base station with an active array supports multi-user joint elevation and azimuth volumetric beamforming (3D beamforming), which results in much higher cell capacity compared to conventional systems. Beamforming network (BFN) is main component of phased array antenna. In the beamforming network, the Butler matrix has been used extensively over the years. The Butler matrix has N input ports and N output port and it consists of 90 degree hybrid couplers and fixed phase shifters. It is used to drive an array of N antenna elements.