A Quad-Band Slant 45° Dual-Polarized Butler-based Omni-Directional MIMO Antenna

This paper presents the design of the compact quad-band slant 45° dual-polarized Butler-based omni-directional MIMO antenna working at the frequency band of 0.69-0.96 GHz (LB), 1.69-2.69GHz (MB), 3.3-4.2 GHz (C-Band), and 5.15-5.93 GHz (HB). The LB array of the proposed antenna consists of three elevation (EL) panels of slant 45° dual-polarized dipoles and two Butler-based azimuth beam formers. Through replacing traditional T-splitter type azimuth beam formers by the Butler matrix 3x3, the omni-directional 6x6 MIMO antenna at LB band can be realized without increasing the size of the antenna.