近场通信与定位:从球面波前模型到电磁场理论

Near-Field Communication and Positioning:From SphericalWavefront Model to Electromagnetic Field Theory

介绍并推导了电磁衍射域的感应近场区域、辐射近场区域、菲涅尔区域和远场区域的边界条件和辐射特征。针对辐射近场区域的通信,介绍了球面波前模型,认为通过球面波前模型可以正确地建模近场通信信号。针对辐射近场区域的定位,球面波前模型不再准确,因此采用电磁场理论去建模近场信道,并提出了一个通用的近场定位模型,进而基于估计理论推导了近场定位的克拉美罗界。

The boundary conditions and radiation characteristics of the reactive near-field,radiative near-field,Fresnel,and far-field regions of the electromagnetic diffraction domain are introduced and derived.For communication in the radiative near-field region,the spherical wavefront model is introduced,through which the near-field communication signal can be modeled correctly.For the positioning in the radia⁃tive near-field region,the spherical wavefront model is no longer accurate.The electromagnetic field theory is used to model the near-field channel and a general near-field positioning model is proposed,and the Cramér-Rao bound of near-field positioning based on the estima⁃tion theory is derived.