A Compact Broadband 16×16 Butler Matrix for Multibeam Antenna Array Applications

This paper presents a compact 16×16 Butler Matrix operated from 9 GHz - 11 GHz. Compared with the traditional structure, the presented network is much simpler and can be easily designed. The number of needed components in the design is only sixty, where the number of crossovers is four. In addition, the designed network can be fully realized in a single layer laminate with the size of 165 mm × 165 mm (5.5λ
₀
× 5.5λ
₀
). It is shown that the maximum simulated output phase error at 10 GHz is only ±8° and the transmission coefficients are in the range of -14.5 ± 1.5dB over the bandwidth. The measured and simulated results agree well. The designed network can be a potential candidate for the one or two dimensional multibeam array antennas.