This article presents a 420-GHz phase imaging system designed in a 40-nm CMOS technology. It consists of a transmitter (TX), based on a multiplier chain, and a receiver (RX), based on a two-step IQ down-conversion. Those chips share an external, 17.5 GHz, reference to secure frequency synchronization between them. To increase the overall system signal-to-noise ratio (SNR), the TX is modulated with a low-frequency sine-wave signal, while a two-way LO power combining is implemented for the RX first mixer. Those techniques result in a measured TX effective isotropic radiated power (EIRP) of 10 dBm and RX noise figure (NF) of 27 dB, leading to the overall SNR of 52 dB (at a distance of 25 cm and a resolution bandwidth (RBW) of 100 kHz). Furthermore, the measured phase-detection root-mean-square (rms) $1\sigma $ precision is equal to 1.7° (on a 400 $\circ $ range, at a distance of 25 cm and processing time of 500 ns), which leads to 3.4- $\mu \text{m}$ range resolution. In addition, the system operation is illustrated in two imaging demonstrations, recognition of the printed text on paper and 3-D imaging. Those demonstrations illustrate the potential of the presented system and terahertz (THz) phase imaging in general.

中文翻译：

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采用 40 纳米 CMOS 技术的 420 GHz 亚 5 微米范围分辨率 TX-RX 相位成像系统

本文介绍了采用 40-nm CMOS 技术设计的 420-GHz 相位成像系统。它由基于乘法器链的发送器 (TX) 和基于两步 IQ 下变频的接收器 (RX) 组成。这些芯片共享一个外部 17.5 GHz 参考，以确保它们之间的频率同步。为了提高整个系统的信噪比 (SNR)，TX 使用低频正弦波信号进行调制，同时为 RX 第一混频器实施两路 LO 功率组合。这些技术导致测得的 TX 有效各向同性辐射功率 (EIRP) 为 10 dBm，RX 噪声系数 (NF) 为 27 dB，导致总 SNR 为 52 dB（在 25 cm 距离和分辨率带宽 (RBW) 下） 100 kHz）。此外，测得的相位检测均方根 (rms) $1\西格玛$ 精度等于 1.7°（在 400 $\circ $ 范围，在 25 厘米的距离和 500 ns 的处理时间），这导致 3.4- $\mu \text{m}$ 范围分辨率。此外，系统操作在两个成像演示中进行了说明，识别纸上打印的文本和 3-D 成像。这些演示说明了所提出的系统和一般太赫兹 (THz) 相位成像的潜力。