In this letter, an improved balanced Colpitts voltage-controlled oscillator (VCO) with a collector-emitter cross-coupled capacitors is presented. The proposed Colpitts structure can introduce a more robust oscillation startup condition. The noise-shifting technique is used to enhance the loaded quality factor of the tank, which improves the phase noise in turn. In addition, three-bit switches composed of enhancement-mode high-electron mobility transistors (E-HEMTs) are utilized to expand the tuning range and reconfigurability of the proposed VCO. In proof of the concept, a VCO prototype is fabricated in a GaAs BiHEMT [enhancement- and depletion-mode high-electron mobility transistor (E/D-PHEMT)] process. The measured results demonstrate the best phase noise of -139.46 dBc/Hz at 1-MHz offset. To the best of our knowledge, this is the lowest phase noise among the reported ones fabricated on-chip with a similar frequency band, and it achieves a wide tuning frequency bandwidth of 21% (2.65-3.27 GHz) with peak figure of merit (FoM) of -192.26 dB and FOMT of -198.8 dB.

中文翻译：

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使用 GaAs BiHEMT 工艺改进的具有低相位噪声的 Colpitts VCO


在这封信中，提出了一种带有集电极-发射极交叉耦合电容器的改进平衡考毕兹压控振荡器 (VCO)。所提出的科尔皮茨结构可以引入更稳健的振荡启动条件。噪声转移技术用于提高谐振腔的负载品质因数，从而改善相位噪声。此外，由增强型高电子迁移率晶体管（E-HEMT）组成的三位开关用于扩展所提出的 VCO 的调谐范围和可重构性。为了证明这一概念，VCO 原型采用 GaAs BiHEMT [增强型和耗尽型高电子迁移率晶体管 (E/D-PHEMT)] 工艺制造。测量结果表明，1 MHz 偏移时的最佳相位噪声为 -139.46 dBc/Hz。据我们所知，这是已报道的具有相似频段的片上制造的相位噪声最低的产品，并且它实现了 21% 的宽调谐频率带宽 (2.65-3.27 GHz)，峰值品质因数 ( FoM) 为 -192.26 dB，FOMT 为 -198.8 dB。