A 5.1% Efficiency, 2.1 Db Conversion Gain Buffer-Less E-band Frequency Quadrupler with T-coil Voltage Swing Optimization

This paper presents a high-efficiency, high-gain buffer-less frequency quadrupler for E-band transceivers. To enhance harmonic generation, a T-coil is integrated into the second stage of the quadrupler, resulting in improved efficiency and conversion gain. Fabricated in 28-nm bulk CMOS process, the quadrupler achieves a peak conversion gain of 2.1 dB and a total efficiency of 5.1 % at 77 GHz with 0 dBm input power, obviating the need for additional buffer stage at E-band. The 3-dB bandwidth spans from 71 to 82 GHz, and the harmonic rejection ratio exceeds 20 dBc, while occupying a core area of 0.086 mm2.