Indoor environments typically contain diverse RF signals distributed across multiple frequency bands, including NB-IoT, Wi-Fi, and millimeter-wave. Consequently, wideband RF modeling is essential for practical applications such as joint deployment of heterogeneous RF systems, cross-band communication, and distributed RF sensing. Although 3D Gaussian Splatting (3DGS) techniques effectively reconstruct RF radiance fields at a single frequency, they cannot model fields at arbitrary or unknown frequencies across a wide range. In this paper, we present a novel 3DGS algorithm for unified wideband RF radiance field modeling. RF wave propagation depends on signal frequency and the 3D spatial environment, including geometry and material electromagnetic (EM) properties. To address these factors, we introduce a frequency-embedded EM feature network that utilizes 3D Gaussian spheres at each spatial location to learn the relationship between frequency and transmission characteristics, such as attenuation and radiance intensity. With a dataset containing sparse frequency samples in a specific 3D environment, our model can efficiently reconstruct RF radiance fields at arbitrary and unseen frequencies. To assess our approach, we introduce a large-scale power angular spectrum (PAS) dataset with 50,000 samples spanning 1 to 94 GHz across six indoor environments. Experimental results show that the proposed model trained on multiple frequencies achieves a Structural Similarity Index Measure (SSIM) of 0.922 for PAS reconstruction, surpassing state-of-the-art single-frequency 3DGS models with SSIM of 0.863.

翻译：室内环境通常包含分布在多个频段上的多样化射频信号，包括NB-IoT、Wi-Fi和毫米波。因此，宽带射频建模对于异构射频系统联合部署、跨频段通信和分布式射频感知等实际应用至关重要。尽管三维高斯泼溅（3DGS）技术能有效重构单频点的射频辐射场，但无法在宽频范围内对任意或未知频率的场进行建模。本文提出一种新颖的3DGS算法，用于统一宽带射频辐射场建模。射频波传播取决于信号频率与三维空间环境（包括几何形状和材料电磁特性）。为解决这些因素，我们引入频率嵌入的电磁特征网络，该网络利用每个空间位置的三维高斯球体学习频率与传输特性（如衰减和辐射强度）之间的关系。基于特定三维环境下包含稀疏频率样本的数据集，我们的模型能够高效重构任意未知频率下的射频辐射场。为评估所提方法，我们构建了一个包含6种室内环境中1至94 GHz频段共50,000个样本的大规模功率角谱（PAS）数据集。实验结果表明，在多个频率上训练的所提模型进行PAS重构时，结构相似性指数（SSIM）达到0.922，超越了SSIM为0.863的当前最优单频3DGS模型。