Compact Millimeter-Wave Endfire Dual-Polarized Antenna Array for Low-Cost Multibeam Applications

A 28-GHz Switched-Beam Antenna with Integrated Butler Matrix and Switch for 5G Applications

“…However, their operating frequencies are not 28 GHz, but 24 GHz [ 21 ], 60 GHz [ 22 , 23 , 24 ], and 1.9–2.4 GHz [ 19 , 20 ]. Many 28-GHz switched-beam antennas can be found in the literature [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. However, they all failed to achieve the full integration like this work, thus they may not be appropriate for this comparison.…”

“…At the time of writing this paper, many switch ICs that can operate in S, C, X, and Ku bands are commercially available, but unfortunately not many in the desired 28-GHz Ka-band. This is why most previous antenna systems have presented only partially integrated prototype results without the switch integration [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ], or employed only in-house proprietary switch circuits [ 21 , 22 , 23 ], even if they had shown fully integrated results. To the best of authors’ knowledge, this work is the first to present a fully integrated 28-GHz switched-beam antenna with a co-integration of a commercially available packaged switch chip.…”

“…Various mm-wave switched-beam antenna systems based on the Butler matrix have been reported previously, including [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ] in Ka-band and [ 13 , 14 , 15 ] in V-band. All of them carefully investigated co-integrated designs and implementations of an array antenna and Butler matrix.…”

“…The mm-wave band design should critically include co-integrated design and implementation processes with full considerations on the inter-connection and inter-coupling issues among the building components. However, none of the previous works [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ] had successfully shown the co-integration of a switch in their antennas. Without incorporating a switch, they only could characterize their antennas by exciting one port of N × N Butler matrix, while terminating other ports with 50-Ω matching resistors [ 10 ].…”

“…Without incorporating a switch, they only could characterize their antennas by exciting one port of N × N Butler matrix, while terminating other ports with 50-Ω matching resistors [ 10 ]. If a switch was additionally integrated in their prototypes, the previous antennas [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ] would possibly encounter drastic and sometimes severe performance degradations.…”