Researchers set 40 Gbps data transmission record

Researchers from Ericsson and Chalmers University of Technology have developed a new type of microwave circuit that could lead to fewer cords, smaller antennas and quicker video transmission.

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

Herbert Zirath says that semiconductor materials development has enabled manufacture of circuits that can transmit high frequency signals with sufficiently high power. The circuits, which are made of the semiconductor material indium phosphide, are so small that a microscope is needed to distinguish the details.

The photo shows the 140 GHz transmitter chip, containing an I-Q modulator, a 3-stage amplifier and a x3 frequency multiplier for the local oscillator. The chip was designed by Sona Carpenter, Herbert Zirath and Mingquan Bao. Data-transmission measurement was done by Simon He. The chip size is 1.6x1.2 mm². Image: Sona Carpenter

Some of the applications for quicker wireless data transmission that Herbert Zirath envisions include major cultural and sports events where high-resolution live films need to be transmitted to screens without any delay or long cables, and communication within and between the large computer rooms where our digital files end up when we place them in ‘the cloud’. Improved wireless transmission can also mean fewer cords in our homes and at our workplaces. The quick circuits are of interest to Ericsson in terms of transmitting signals to and from base stations and cellular towers.

“This is a very exciting area to be involved in, since the heavily increasing amount of data demands new solutions all the time. The fact that an increasing number of people are watching films wirelessly is the primary reason underlying the need for quicker transmission today.”

The project is being funded by the Swedish Foundation for Strategic Research, and the next step for the project’s researchers involves moving from the laboratory to the outdoors to test the circuits under real circumstances. Even though there are many aspects that have to fall into place for successful data transmission, Herbert Zirath is not nervous. Within a few years, the goal within the project is to demonstrate wireless data transfer of 100 Gbps. “I believe it is only a matter of a couple of years before our circuits will be used in practical applications.”