A 3D Compact Wideband 16×16 Butler Matrix for 4G/3G Applications

This paper presents the design and implementation process of a compact wideband 16×16 Butler Matrix as a beamforming network for 4G and 3G applications, featuring compact wideband branch-line hybrid couplers, Schiffman phase shifters and a 3D approach of the conventional 16×16 Butler Matrix. The 16×16 Butler Matrix operates from 1.65 GHz to 2.17 GHz with insertion losses around -16.5 dB±1.2 dB and maximum phase imbalance of ±15° for phase difference between output port signals.