This article presents an overview and analysis of spatial-to-spectral harmonic-modulated arrays (SHAs). Compared to traditional analog or digital beamforming arrays, SHAs enable concurrent multi-beamforming without requiring substantial hardware replication. SHAs replace the need for hardware replication with frequency-domain multiplexing. Furthermore, SHAs have the potential to become key contributors to future 6G networks by enabling scalable multi-user communications, joint communication and sensing, and spatial interference mitigation. In addition, an analysis of the SHA's harmonic-modulation waveform and its effects on gain, noise and bandwidth is presented. A comb-like modulation waveform for SHAs that minimizes spectral inefficiency is proposed. Further, an analysis of the SHA's capability to independently steer multiple beams is presented. This capability is quantified in terms of the SHA's spatial-to-spectral degrees of freedom. Lastly, this work introduces a novel SHA architecture that provides three spatial-to-spectral degrees of freedom with minimal hardware replication.

翻译：本文对空间-频谱谐波调制阵列（SHAs）进行了综述与分析。相较于传统的模拟或数字波束赋形阵列，SHAs能够在无需大量硬件复制的条件下实现并发多波束赋形。SHAs通过频域复用技术替代了硬件复制的需求。此外，SHAs通过支持可扩展的多用户通信、联合通信与感知以及空间干扰抑制，有望成为未来6G网络的关键组成部分。文中还分析了SHA的谐波调制波形及其对增益、噪声和带宽的影响，并提出了一种能最小化频谱效率损失的梳状调制波形。进一步地，本文分析了SHA独立控制多个波束的能力，该能力通过SHA的空间-频谱自由度进行量化。最后，本研究提出了一种新颖的SHA架构，该架构能以最少的硬件复制提供三个空间-频谱自由度。