Achieving Quasi-Planar Coverage: A Concave Meniscus Lens-Enhanced Rotman-Lens-Based mmID for Ultra-Long-Range IoT Applications

Recent advancements in 5G/millimeter-wave (mmWave) technologies have led to the development of next- generation IoT devices that provide large-scale connectivity and high data rates. To ensure reliable communication and consistent performance, these devices must have wide angular coverage and high detectability, allowing them to maintain stable connectivity regardless of their orientation or positioning. In this work, we introduced a 3-D lens-enabled semipassive millimeter-wave identification (mmID) for next-generation Internet-of-Things (IoT) systems, capable of quasi-planar angular coverage and ultra-long range capabilities. The system employs a concave meniscus dielectric lens combined with a Rotman-lens-based mmID, achieving a peak differential radar cross section of −15.1 dBsm and near-planar 3 dB angular coverage of $\pm$${\text{85}}^{\circ }$. Using a proof-of-concept frequency-modulated continuous wave (FMCW) radar, the mmID demonstrated detection at an ultra-long range of 68 m at incident angles of ${\text{15}}^{\circ }$ and ${\text{85}}^{\circ }$, with an average localization error of 4 cm. Furthermore, utilizing the maximum allowable 75 dBm equivalent isotropic radiated power in 5G applications, the proposed system has a projected theoretical maximum range of 1.3 km and 1.02 km at incident angles of 15$^{\circ }$ and 85$^{\circ }$, respectively, making it a promising solution for next-generation orientation-agnostic IoT applications.