Millimeter-Wave Multi-Beam Waveguide Lens Antenna

A millimeter-wave multi-beam antenna operating dual-band with a 1 GHz bandwidth each, around the 28 and 31 GHz frequencies, is presented. The antenna is designed on the principle of transformation of the cylindrical wavefront to planar to enhance the gain. A metal ridge lens is used for the wavefront transformation by a phase extraction and compensation method. The dual-band operation of the antenna aids in transmitting and receiving at two independent frequencies. An advantage to this is the significant reduction of the number of RF chains due to the use of the shared aperture over the lens. The antenna has been validated for casting the beam in three primary target directions of -60 degrees, 0 degrees, and 60 degrees, however, other beam directions can be suitably designed. The spatial footprint of the antenna is 170 mm x 150 mm and has a gain varying between 14 and 15 dBi at each of the three ports centered around 28 and 31 GHz. The theoretical simulated results are in good agreement with the measurements. The antenna could potentially be used in 5G small cell deployments of a millimeter-wave local multipoint distribution system (LMDS).