New Microwave Circuit from Chalmers University of Technology Operates at 140 GHz

The desire for higher data rates is driving research into circuits for communications at frequencies above 100 GHz. A Swedish group from Chalmers University of Technology and Ericsson has been successful in building data circuits that can function at these frequencies.

“We have designed circuits for signals at 140 Gigahertz, where we have a large bandwidth,” said Herbert Zirath, a professor in high speed electronics at Chalmers who is employed by Ericsson Research on a part-time basis. “In laboratory testing, we have achieved a transmission rate of 40 Gigabit data per second, which is twice as fast as the previous world record at a comparable frequency.”

The circuits are made from the semiconductor indium phosphide and are so small a microscope is needed to distinguish the details. Ericsson is interested in the circuits for use in transmitting signals to and from base stations and cellular towers.

The project is being funded by the Swedish Foundation for Strategic Research. The next step for Zirath and his team is to test the circuits outdoors. Zirath said his goal is to demonstrate wireless data transfer of 100 Gigabits per second. “I believe it is only a matter of a couple of years before our circuits will be used in practical applications,” he said.

The researchers talked about their results at this week's Compound Semiconductor Integrated Circuits Symposium in San Diego during the “Breaking News Papers” session.

Doug Lung

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.