This brief presents the CMOS fractional-N frequency synthesizer for UHF RFID reader applications. With stringent phase noise (PN) specifications for UHF RFID transceiver, our proposed synthesizer is designed to have a narrow loop bandwidth and 2nd2^{nd} -order loop filter as the optimum solution paired with low noise VCO. Then, we propose the transformer-based impulse sensitivity function (ISF) manipulating VCO that supports the target PN of the frequency synthesizer, albeit with large pass-band characteristic. Compared to conventional ISF manipulating VCO, our proposed solution improves the PN by 11.3 and 14.7 dB at 10 kHz and 1 MHz offset frequencies, respectively. Figure of merit (FOM) is also superior to conventional one by 7.4 and 10.9 dB at aforementioned offset frequencies. The frequency synthesizer is implemented in a 55nm CMOS technology as a part of the UHF RFID transmitter and consumes 38.4 mW power with 0.413 mm2mm^{2} active area. With comparison to the state-of-the-art frequency synthesizer at sub-6GHz operating frequency, only our solution satisfies the target PN for EPC global standard and various local regulations across the entire UHF RFID operating frequency range.

中文翻译：

---

用于 UHF RFID 读取器应用的 CMOS 小数 N 频率合成器，具有基于变压器的 ISF 操作 VCO


本简介介绍了适用于 UHF RFID 读取器应用的 CMOS 小数 N 频率合成器。根据 UHF RFID 收发器严格的相位噪声 (PN) 规范，我们提出的合成器设计为具有窄环路带宽和 2nd2^{nd} 阶环路滤波器，作为与低噪声 VCO 搭配的最佳解决方案。然后，我们提出了基于变压器的脉冲灵敏度函数 (ISF) 操纵 VCO，该 VCO 支持频率合成器的目标 PN，同时具有大的通带特性。与传统的 ISF 操纵 VCO 相比，我们提出的解决方案在 10 kHz 和 1 MHz 偏移频率下分别将 PN 提高了 11.3 和 14.7 dB。在上述偏移频率下，品质因数 (FOM) 也比传统品质因数高出 7.4 和 10.9 dB。该频率合成器采用 55nm CMOS 技术实现，作为 UHF RFID 发射器的一部分，功耗为 38.4 mW，有效面积为 0.413 mm2mm^{2}。与低于 6GHz 工作频率的最先进频率合成器相比，只有我们的解决方案在整个 UHF RFID 工作频率范围内满足 EPC 全球标准和各种当地法规的目标 PN。