Passive Millimeter Wave Reflector

The mmWave band (26GHz-30GHz), used in 5G wireless, suffers high or total attenuation due to obstacles (LOS). To overcome this loss of signal, this invention brings a low cost solution for coverage extension in broadband indoor applications. The solution consist in a set of modular passive reflectors, with convex main surface rugged with concave grooves and convex mounds. The modules have polygonal shapes suitable for a variety of installation configurations. The passive reflector modular system reflects the directive beam coming from the transmitter antenna and produces a diffuse spread signal resulting in a wider coverage. The incident angles can vary. The design has been checked by simulations, validated with prototypes and tested in laboratory. The millimeter frequency band (mmWave) is used in 5G wireless communications for short range and broadband scenarios, mostly indoors. This band (26GHz-30GHz) is subject to high attenuation in free space LOS (direct Light-of-Sight) and even more relevant or complete attenuation in NLOS (Non Light-of-Sight) due to fixed or mobile obstacles. Some solutions, with active power requirements, have been proposed and developed to reduce NLOS, including beam-forming and beam-steering techniques, multiple antennas and multiple active repeaters, as well as the use of high-power transmitters and very sensitive receivers. Nonetheless, almost all of these strategies proposed are complex and expensive, thus they are not always feasible to be deployed. The technology in this invention is mmWave signal diffuse reflection, with the aim of low cost manufacturing, deployment and maintenance. To achieve this objectives the solution developed is an architecture of passive reflectors (i.e. with no need of electrical power, neither cabling) with the following characteristics: · Convex main surface / surfaces · Modular, with polygonal mounting (for instance hexagonal) · Rough / irregular surface (concave grooves roughness over main surface) · Metal or metalized surface The use of passive re¿ectors is an ef¿cient cost/bene¿t solution to enrich the channel response and to improve the coverage. The described characteristics are the result of simulation, design and test of different alternatives for the shape and the surface of the passive reflector.