In the above article, Hong et al. proposed a frequency region beamforming scheme exploiting frequency diverse subarray. We found that there is a mathematical flaw in precoding vector normalization in their sidelobe randomization scheme called the inverted subarray subset technique (ISST). We show that it is not only a matter of how to define and interpret the array factor, but it leads to the wrong performance optimization and misoperation of their own proposed scheme, which may cause detrimental security risks. Furthermore, to avoid any false conclusions in the future study caused by the irrational normalization, we also present the related techniques and their correct normalization.

中文翻译：

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关于“使用倍频子阵列进行安全毫米波无线通信的固定区域波束成形”的评论

在上面的文章中，洪 等。提出了一种利用频率分集子阵列的频率区域波束形成方案。我们发现在旁瓣随机化方案中，预编码矢量归一化存在数学缺陷，称为反向子阵列子集技术（ISST）。我们证明，这不仅是如何定义和解释阵列因素的问题，而且还会导致错误的性能优化和他们自己提出的方案的误操作，这可能会带来不利的安全风险。此外，为了避免在将来的研究中由于非理性归一化而产生的任何错误结论，我们还介绍了相关技术及其正确归一化。