Taiwan’s semiconductor foundry service provider United Microelectronics Corp. (UMC) has fabricated a push-push voltage-controlled oscillator (VCO) with an operating frequency of 192 GHz using its 0.13 µm RF CMOS process technology. According to UMC, 192 GHz is the highest operating frequency for any silicon-based circuit to date. The chip was developed by the Silicon Microwave Integrated Circuits and Systems Research Group (SIMICS), Department of Electrical and Computer Engineering at the University of Florida, Gainesville, which also introduced a record-setting 105 GHz VCO produced by UMC in last June.

High-frequency oscillators such as the 192-GHz VCO, manufactured by UMC, can potentially be used for advanced remote sensing and imaging applications to accomplish chemical detection, detection through fabric, imaging through fog and clouds, and the detection of skin cancer.

Oscillators are known for generating signals at normal operating frequencies and can be pushed to 2X, 3X, 4X the frequency, etc. However, signals at these higher frequencies are often too weak to be effective. Because the VCO core operating frequency in push-push VCOs is one-half of the output frequency, besides higher device gain, varactor and capacitor Q factors are also higher, while the transmission line loss is lower--resulting in a stronger signal. The VCO provides output power of ~-20 dBm and phase noise of ~-100 dBc/Hz at 10 MHz offset, while consuming 11 mA from a 1.5-V supply. This work has been supported by DARPA and is published in a paper written by Changhua Cao, Eunyoung Seok and Kenneth O in the Feb. 16 issue of IEE Electronics Letters.

“UMC’s proven RF CMOS technology is currently being used to power a broad range of advanced wireless applications,” said Patrick T. Lin, chief SoC architect, system & architecture support at UMC. “The VCO developed by the University of Florida also demonstrated that UMC’s RFCMOS technology is well suited for designs that require extreme levels of performance. We are excited about the technological achievements that we have accomplished with the university to date and look forward to offering the fruits of these developments to the mainstream RF design community.”

“This is particularly exciting because we produced the VCO using a 0.13-µm CMOS process,“ said Professor Kenneth O. “We also have a 140-GHz fundamental VCO running in our lab, which has been fabricated using UMC’s 90-nm logic process. It should be a straightforward matter to turn this into a push-push VCO to generate ~280-GHz signal. Furthermore, if a 65-nm process is used, we can probably reach 350-400 GHz. Generating a THz signal in CMOS technology is not far off.”

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