Engineers at the University of Florida and Taiwan-based United Micro Electronics Corp. have built a 105-GHz circuit using standard CMOS technology. The advance could lead to inexpensive systems for detecting hidden weapons, and chemical and biological agents.

Ultrahigh-frequency circuits are nothing new, but earlier versions needed exotic materials to work, making them too costly for commercial use. The previous speed record for CMOS circuits was 103 GHz. But that circuit consumed four times more power than the UF device and was built using a more advanced technology. In a related development, UF researchers fabricated a CMOS Schottky diode that operates at frequencies to 1.5 terahertz, which is also a record for mainstream silicon technology. Such diodes should make it possible to build circuits that operate at about 400 GHz, say researchers. Circuits capable of terahertz speeds could follow in a couple of years.

Potential applications for the devices are in systems that detect chemical and biological weapons. The circuits' high operating frequency closely matches the vibration frequency of chemical bonds that make up the toxic agents. Other applications include automotive crash-avoidance radar, adaptive cruise control, parking assistance, and obstacle-detection systems.