Quasi 2-D Field Reconstruction Using the Conjoint Cylindrical Wave Expansion

Off-the-horizon propagation severely degrades the accuracy of any field reconstruction technique that presupposes a two-dimensional (2-D) wireless channel. Therefore, employing the 2-D cylindrical wave expansion (CWE) to interpolate perimeter channel measurements into a planar region often yields poor results. Here, the CWE is adapted for real-world radio channel measurements by selectively combining the basis functions from two similar CWEs. Using both simulated and experimental measurement data, it is shown that this conjoint CWE yields a more accurate reconstruction than the conventional CWE yet requires no additional measurements. Thereby, this field reconstruction-based channel imaging technique will enable more complete investigations of the wireless channel's spatial behavior and allow researchers to isolate and characterize the actual mechanisms underlying radio wave propagation.