Emerging smart antenna systems requiredifferent beam patterns of multiple antennas. Although adjustable phaseshifters are mostly used in continuous-beam systems, the Butler matrix is usedin switching-beam systems due to its low cost and easy fabrication. In thisstudy, an antenna-array-feeding circuit based on the Butler matrix that can beused for Multiple Input Multiple Output applications is designed for 5G newradio. With the proposed switching system, the control of four beams can beachieved. The Butler circuit, designed to cover the 3.5–4.2 GHz 5G band, has alow complexity and is capable of meeting the need for high data throughput. A simulationof the circuit and circuit sub-elements designed using a 0.508-mm-thicksubstrate material is performed using the Computer Simulation TechnologyMicrowave Studio computer-aided design tool. Furthermore, a prototype of theButler circuit is fabricated, and the amplitude and phase variations at theoutput ports are measured. An average transmission loss of the feed circuit ismeasured as 1.5 dB, and when the length of the Phase Shifter in the circuit isset to λ/8, with a four-element linear array added to the output of the Butlercircuit, the main beam is steered to ±15o and ±35o having maximum gain in the6.39–8.77 dBi range.
Cite this article as: Türker Tokan N. ArrayAntenna Feeding Network Design for 5G MIMO Applications. Electrica, 2019;19(2): 120-127.