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.
Bibliographical noteFunding Information:
The authors thank the TSMC University Shuttle Program for chip fabrication and Sonnet for software support. They also acknowledge the support of the C2S2 Focus Center under FCRP, an SRC entity, and the National Science Foundation.
Copyright 2013 Elsevier B.V., All rights reserved.
- coupled oscillator
- distributed systems
- frequency tuning
- harmonic generation
- nonlinear dynamics
- phase shifter
- power combining