A 105-GHz VCO With 9.5% Tuning Range and 2.8-mW Peak Output Power in a 65-nm Bulk CMOS Process

作者：Adnan Muhammad^*; Afshari Ehsan

来源：IEEE Transactions on Microwave Theory and Techniques, 2014, 62(4): 753-762.

DOI：10.1109/TMTT.2014.2309940

• Capacitive tuning
• Colpitts
• coupled oscillators
• millimeter wave
• voltage-controlled oscillator (VCO)

To demonstrate high tuning range and large output power, we propose a loop of coupled oscillators in this work. Two different tuning mechanisms are simultaneously exploited. First, each core oscillator is tuned using a variable capacitor. Next, by controlling the phase/delay between the coupled oscillators, the entire loop dynamics, and hence, its frequency is tuned. In this paper, we analyze a loop of "n" coupled oscillators using Adler's equation and derive the expression for the maximum tuning range. Perturbation analysis is used to study the stability conditions of the loop of coupled system. The analysis is extended toward a nested loop of coupled oscillators. The activity condition from two-port theory is used to squeeze maximum power out of active devices. The proposed system is designed and implemented using four coupled Colpitts voltage-controlled oscillators (VCOs) in a 65-nm bulk CMOS process. The VCO achieves continuous tuning range of 9.5% at the center frequency of 105 GHz with the peak output power of 2.8 mW. The circuit consumes 54 mW from a 1.2-V supply. To the best of our knowledge, this VCO has the highest output power and tuning range among all the CMOS oscillators at or above 100 GHz.

• 出版日期2014-4