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arXiv · 2511.00502

Impact of Antenna Arrays Misalignment on the Near Field Distance in Terahertz Communications

Peng Zhang·Vitaly Petrov·Emil Björnson
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Abstract

The extremely short wavelength of terahertz (THz) communications leads to an extended radiative near-field region, in which some canonical far-field assumptions fail. Existing near-field boundary formulations (Fraunhofer distance) for uniform linear/planar array (ULA/UPA) configurations assume ideal alignment between transceivers, overlooking practical misalignments caused by mobility or mechanical imperfections. This paper addresses this critical gap by analyzing the impact of spatial misalignment on near-field distance calculations in THz systems. We derive exact analytical expressions and simplified approximations for the near-field boundary in both ULA--ULA and UPA--UPA configurations under arbitrary misalignment offsets. Through numerical simulations, we validate our theoretical models and quantify how misalignment reshapes the near-field region. These findings provide essential guidelines for optimizing THz system deployment in realistic scenarios.

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Peng Zhang, Vitaly Petrov, Emil Björnson. 2025-11-01. Impact of Antenna Arrays Misalignment on the Near Field Distance in Terahertz Communications. https://arxiv.org/abs/2511.00502

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