This letter presents a novel compact power amplifier (PA) using the transformer-based quadrature coupler as the power splitter and combiner to achieve a large output power and high gain for automotive radar application. Compared with conventional transmission-line-based power splitter and combiner, the transformer-based quadrature coupler offers a low loss, wide bandwidth, and compact footprint. As a proof of concept, a 77-GHz PA is designed and implemented in a 65-nm CMOS technology. The measured small-signal power gain is 26.4 dB with a 8.5-GHz 3-dB bandwidth from 74 to 82.5 GHz. The measured $P_{\text {sat}}$ , OP_{1 dB}, and peak power added efficiency (PAE) are 15.82, 11.5 dBm, and 15.9%, respectively. In addition, the saturated output power at 77 GHz is 16.5 dBm at −40 °C and still remains as high as 13.5 dBm at 130 °C, which enables the automotive application. The proposed PA occupies a core area of $270\,\,\mu \text{m}\,\,\times 530\,\,\mu \text{m}$ and the total dc power consumption is 240 mW.

中文翻译：

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使用基于变压器的正交耦合器网络具有 15.9% PAE 的 26.4dB 增益 15.82dBm 77GHz CMOS 功率放大器

这封信介绍了一种新型紧凑型功率放大器 (PA)，使用基于变压器的正交耦合器作为功率分配器和组合器，可为汽车雷达应用实现大输出功率和高增益。与传统的基于传输线的功率分配器和组合器相比，基于变压器的正交耦合器具有低损耗、宽带宽和紧凑的占地面积。作为概念验证，77-GHz PA 是采用 65-nm CMOS 技术设计和实现的。测得的小信号功率增益为 26.4 dB，74 至 82.5 GHz 的 8.5 GHz 3 dB 带宽。被测 $P_{\text {sat}}$ 、OP _{1 dB}和峰值功率附加效率 (PAE) 分别为 15.82、11.5 dBm 和 15.9%。此外，77 GHz 时的饱和输出功率在 -40 °C 时为 16.5 dBm，在 130 °C 时仍高达 13.5 dBm，这使得汽车应用成为可能。拟建的保护区占据核心区域 $270\,\,\mu \text{m}\,\,\times 530\,\,\mu \text{m}$ 总直流功耗为 240 mW。