New telephones and other digital devices are increasing the amount of signal capacity we require from wireless communication relay stations. One estimate from Fairchild Semiconductor International indicates that 5.3 million new base stations will be deployed over the next three years to handle the increased demand. A new, patented radio frequency (RF) transistor technology invented by Jayant Baliga, a North Carolina State professor of electrical engineering, may help handle the increased demand for digital capacity. "My unique patented transistor structure allows supporting the voltage with very small space on the die surface using the principle of drift region engineering," says Baliga. "This approach allows making the transistors channel length very short, resulting in improved transconductance, linearity, and gain at RF frequencies," he says. The drift regions are doped at higher levels in the transistor, which improves the efficiency and lowers conductance. Baliga says his RF transistors exceed the capacity of current technology—lateral double-diffused metal oxide semiconductor field effect transistors (LDMOSFETs). His technology provides an increase in RF power gain that is five to ten times greater than a silicon LDMOSFET. He adds that his transistors result in greater signal linearity and reduce the amount of cross talk distortion during telephone conversations. The transistors are made using silicon as the semiconductor material, so they can be built using existing semiconductor fabrication processes. This transistor technology is suitable for all cellular base stations at all power levels (pico-stations, micro-stations, etc). It can be used in RF power amplifiers for any analog or digital system. Baliga founded Silicon Wireless Corp. with seed money from NC State Centennial Venture Partners Fund and Longleaf Venture Fund. They expect to have product on the market in the forth quarter of 2001. Contact Baliga at Silicon Wireless Corp., 920 Main Campus Dr., Suite 400, Raleigh, NC 27606; Tel: (919) 424-3770, Fax: (919) 424-3771.
These free camps are designed for children ages 10 to 18. Attendees are introduced to 3D CAD software and shown how 3D printers can make their work a reality. Many classes were nearly 50 percent girls and 50 percent boys.
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