▸创新点1：高效谐波生成技术（方法创新） - 通过精确控制漏极电流的斩波操作，实现了谐波丰富的频谱生成，并通过偏置电压调节频谱形状，显著提升了谐波生成效率，为后续谐波抑制奠定了基础。
▸创新点2：注入锁定技术（电路创新） - 利用频率调制（FM）和幅度调制（AM）特性，有效抑制了谐波杂散，同时实现了高精度的频率锁定，在28 GHz和39 GHz下分别实现了57.7 dBc和51.7 dBc的谐波抑制比。
▸创新点3：可调谐四阶谐振器（系统创新） - 采用可调谐的四阶谐振器结构，实现了对目标谐波的精准选择和非目标谐波的高效抑制，进一步提升了系统的整体谐波抑制能力。
▸创新点4：多比率（MR）频率乘法器（系统创新） - 通过集成×5和×7两种可切换的乘法比率，提供了灵活的频率生成方案，同时保持了高谐波抑制性能，扩展了应用场景。
Abstract
Frequency multipliers are key components for high- quality millimeter-wave signal generations. However, the har- monic spurs generated by the frequency multipliers significantly affect the system performance. As a result, a high harmonic rejection is required in the frequency multiplier design. In this article, we present a multi-ratio (MR) frequency multiplier that exhibits ×5a n d ×7 switchable multiplication ratios. Three processes of frequency multiplication, harmonic generation, har- monic amplification, and harmonic selection, are analyzed, and the corresponding techniques for harmonic suppression are introduced. The harmonic spurs can be suppressed by these three techniques: high-efficiency harmonic generation, injection locking, and tunable fourth-order resonator. First, the high- efficiency harmonic generation is realized by chopping the drain current, which enables a harmonic-rich spectrum to be generated, and the shape of the spectrum can be controlled by the biasing voltage. The second technique, injection locking, can suppress the harmonic spurs by its frequency-modulation (FM) and amplitude-modulation (AM) nature. The third technique, the tun- able fourth-order resonator, can select the desired harmonic and suppress others. An MR injection-locked frequency multiplier was implemented in a 65-nm CMOS process as the proof-of- concept design. The multiplier operates from 22.4 to 40.6 GHz, and the measured harmonic rejection ratio is 57.7 dBc at 28 GHz and 51.7 dBc at 39