A 270-Ghz Fully-Integrated Frequency Synthesizer in 65nm CMOS

A fully-integrated sub-THz frequency synthesizer is proposed leveraging an RF sub-sampling PLL (SS-PLL) cascaded with an ILFM-based mm-Wave LO generation chain and a sub-THz mixer for frequency extension. Third-harmonic and fourth-harmonic extraction enhancement methods are proposed for the ILFMx3 and ILFMx4, respectively. A distributed biased technique is proposed to improve the linearity of the magnetic tuning sub-THz ILFMx6. In addition, a frequency tracking loop (FTL) with frequency and amplitude calibration is proposed for the ILFMs. The 65nm CMOS prototype measures a locking range from 61.2-to-100.8GHz, 122.4-to-136.8GHz, and 198.5-to-273.6GHz, phase noise from -79.3dBc/Hz to -95.4dBc/Hz at 1-MHz offset, an integrated jitter from 124fs to 159fs, and an output power of -11dBm and DC-to-RF efficiency of 0.16% at a carrier of 211.4GHz.