Wireless Coupled Single Conductor Surface Wave Propagation for Industrial Internet-of-Things: Measurement and Modeling

Studies on novel sub-6GHz indoor surface wave communication channel models are presented. With the aid of a surface wave launcher that based on planar magnetic dipole antennas, a wireless coupled, indoor surface wave channel measurement apparatus is constructed to validate the channel characteristics, i.e., path loss, channel impulse response, and channel capacity. As validated in the 2.5-4.5GHz band, the path loss can be reduced by 30dB compared to the free-space propagation case, owing to the sufficient excitation and propagation of the surface wave mode. In addition, scattering paths can be clearly identified with mitigated multi-path effect. Unlike traditional coaxial surface wave launchers that cascading with the transmission line in a wired fashion, the surface wave launcher is coupled to a long, single conductor line with length longer than 30 wavelengths that emulating the long, bulky conductors in Industrial Internet-of-Things (IIoT) in a wireless manner. Therefore, the wireless IIoT nodes can be flexibly networked and deployed as desired in a low-loss fashion with less multi-path effect. The conceptual propagation scheme and channel modelling approach is expected to benefit the design and deployment of IIoTs.