A Novel CMOS High-Power Terahertz VCO Based on Coupled Oscillators: Theory and Implementation

• Published in: IEEE journal of solid-state circuits Vol. 47; no. 12; pp. 3032 - 3042
• Main Authors: Tousi, Y. M., Momeni, O., Afshari, E.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01-12-2012; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Circuit properties; CMOS; coupled oscillator; Couplings; Design. Technologies. Operation analysis. Testing; Diodes; distributed systems; Electric, optical and optoelectronic circuits; Electronic circuits; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Exact sciences and technology; frequency tuning; Harmonic analysis; harmonic generation; Integrated circuits; matching; nonlinear dynamics; Oscillators, resonators, synthetizers; phase shifter; power combining; Power generation; Resonant frequency; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Terahertz; Tuning; VCO; Voltage-controlled oscillators; Harmonic; Coupled oscillator; Output power; VCO; Non linear control; Power supply; Implementation; matching; Cut off frequency; CMOS; Frequency shift; Power combiners; Complementary MOS technology; distributed systems; Terahertz; nonlinear dynamics; frequency tuning; power combining; Semiconductor materials; Phase shift; Voltage controlled oscillator; Power electronics; Harmonic generation; Distributed system; Tuning; Phase shifter; Combiner circuit; Varactor diode; THz range; High power
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2012.2217853

We introduce a novel frequency tuning method for high-power terahertz sources in CMOS. In this technique, multiple core oscillators are coupled to generate, combine, and deliver their harmonic power to the output node without using varactors. By exploiting the theory of nonlinear dynamics, we control the coupling between the cores to set their phase shift and frequency. Using this method, two high-power terahertz VCOs are fabricated in a 65 nm LP bulk CMOS process. The first one has a measured output power of 0.76 mW at 290 GHz with 4.5% tuning range and the output power of the second VCO is 0.46 mW at 320 GHz with 2.6% tuning range. The output power of these signal sources is 4 orders of magnitude higher than previous CMOS VCOs and is even higher than VCOs implemented in compound semiconductors with much higher cut-off frequencies.