Design of Low-cost All Metal Electromagnetic Lens Based on Near-field Energy Focusing

Exploring the application scenarios of energy focusing lenses has become an important topic in contemporary scientific discourse, given that the manufacturing cost of these lenses directly affect their applicability and extension in many field. Thus, maintaining lens focus efficacy while reducing production costs is a pursuit of utmost significance. A four-layered all metal energy focusing lens is proposed, which is operating at 2 GHz frequency, each layer comprising of 400 units. In this article, the configuration of lens units is designed, which in turn modifies the path of radiation current of electromagnetic waves within these units, thereby enabling precision control over the phase each unit generates. By compensating for the phase differentials instigated by varying distances between the feed antenna and each lens unit, the arrangement order of the units has been modified accordingly. This adjustment facilitates the electromagnetic energy to converge onto the expected focal spot subsequent to its passage through the lens. The novelty of this study lies in the distinctive approach of fabricating lens units from metal, dispensing with the traditionally most expensive component of lenses which consequentially leads to a substantial reduction in lens production costs. Simulation results elucidate that the all metal lens can generate good energy focusing effect of electromagnetic energy within a distance of 0.3 m to 0.75 m from the lens, forming ellipsoidal focal spots. When the distance is greater than 0.75 m, the electromagnetic energy decays faster. Hence, the all-metal energy-focusing lens fabricated in our study exhibits potential applications in numerous domains operating within the near-field ambit of an antenna, such as near-field target detection, etc.