A 4.2-to-4.6 GHz 8-shaped-inductor based LC-VCO with an orthogonal-coupled triple-coil transformer is presented in this brief. The orthogonal-coupled triple-coil transformer is designed to reduce magnetic coupling and improve phase noise. The mutual inductance between the 8-shaped inductor and the tail-filtering inductor is negligible due to the symmetrical and reversal magnetic field generated by the two loops of the 8-shaped inductor, which avoids the additional chip area occupation of the bulky tail-filtering inductor. In addition, an 8-shaped transformer with thin line width is proposed to bias the varactor instead of using resistors, which avoids the resistor thermal noise contribution. The VCO is implemented in a 180 nm CMOS process, which consumes 7.4 mA current from a 1 V power supply. By adopting the 8-shaped inductor with noise filtering and noise-free biasing technique from the orthogonal-coupled triple-coil transformer, the measured phase noise achieves −149.3 dBc/Hz at 10 MHz offset away from a 4.3 GHz carrier and the resulting figure-of-merit (FoM) is −193.2 dB. To the best knowledge of the authors, this brief presents the VCO with the best FoM among published 8-shaped-inductor based LC-VCOs.

中文翻译：

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基于 4.4GHz 193.2dB FoM 8 形电感的 LC-VCO，使用正交耦合三线圈变压器

本简介中介绍了一种基于 4.2 至 4.6 GHz 8 形电感器的 LC-VCO，该 LC-VCO 具有正交耦合三线圈变压器。正交耦合三线圈变压器旨在减少磁耦合并改善相位噪声。由于8字电感的两个回路产生对称反向磁场，8字电感与尾部滤波电感之间的互感可以忽略不计，避免了笨重的尾部滤波对芯片面积的额外占用电感器。此外，提出了一种细线宽的 8 形变压器来偏置变容二极管，而不是使用电阻，从而避免了电阻热噪声的影响。VCO 采用 180 nm CMOS 工艺实现，从 1 V 电源消耗 7.4 mA 电流。通过采用来自正交耦合三线圈变压器的具有噪声过滤和无噪声偏置技术的 8 形电感，在偏离 4.3 GHz 载波的 10 MHz 偏移处，测量的相位噪声达到 -149.3 dBc/Hz，得到的数字优点 (FoM) 为 -193.2 dB。据作者所知，本简报介绍了已发表的基于 8 形电感的 LC-VCO 中具有最佳 FoM 的 VCO。