Shaped Lens Antenna for 5G Mobile With Wide Angle Multi-Beam and Optimum Feed Position

Millimeter wave operation in 5G base stations necessitates small cell size and advanced multi-beam capabilities. At millimeter waves, base station antennas must be highly compact, making dielectric lens antennas with excellent multi-beam radiation patterns an ideal choice. To ensure lightweight and easy installation, it is crucial to design lenses with minimal thickness and curvature. This study applies a lens shaping method for Abbe’s sine condition to the newly developed straight line condition (SLC) to validate the method’s ability to produce a thin lens with good performance. The designed lens, operating at 28GHz, has a diameter of 202 mm and a thickness of 63 mm. The optimum feed positions for multi-beam operations are determined by focal region ray tracing. Additionally, the impact of feed position errors on radiation pattern degradation is analyzed to ensure accurate measurements. Electromagnetic simulator calculations demonstrate wide-angle multi-beam performance from 0° to 30°. The calculated results are compared with measured results from a fabricated lens antenna, showing good agreement in multi-beam radiation patterns and antenna gain variations. Consequently, the study confirms the achievement of a thin lens with small curvature and excellent multi-beam radiation patterns.