Research Projects

Millimeter-wave (mm-wave) frequency bands have been studied in recent years for 5G mobile communications, primarily to achieve higher data transfer rates. High-gain antenna systems are necessary for these applications to compensate for mm-wave path losses. However, a high-gain antenna with a narrow beamwidth can cover only a small area and also suffers from transmission blockages between mobile devices in line-of-sight (LOS), even when the obstruction is small. Therefore, an electronic beam-scanning antenna with a higher gain is necessary to overcome these challenges. A lens antenna is suitable for such mm-wave 5G applications because of its wide bandwidth and high gain features. A lens antenna that can switch beams over wide angles has been demonstrated recently. Despite their complexity and bulkiness, these designs suffer from high scan losses, limiting their practical applications. The gradient-index (GRIN) lens, which has a radially varying refractive index, is relatively compact and lightweight and can scan beams over a wide angle. However, a lens antenna has a large overall size, especially when its diameter D and/or focal length F are also large. It is possible to design an antenna with a smaller F, but the lens would need to be thick and bulky. Electronic beam-switching antennas must also scan beams continuously to cover a wide area. It is exceptionally challenging to realize such continuous beam-scanning over a wide bandwidth, particularly for mm-wave frequency bands. This work aims to realize a compact and wideband design of a switched-beam GRIN lens antenna for mm-wave 5G applications. An array of waveguide and horn feeds will be placed in the focal plane of the lens and feed elements will be excited one at a time and switched to achieve 2D beam scanning over wide scan angles.