IBM Transceiver Pushes Envelope For Radar Imaging

IBM researchers have again pushed the technological envelope – this time inventing a semiconductor that brings together four integrated circuits (ICs) and 64 antennas in a single package for mobile and transportation systems.

IBM officials said Big Blue scientists – in an effort partially funded by the Defence Advanced Research Projects Agency (DARPA) – have achieved a milestone in creating a phased-array transceiver that contains all of the millimetre-wave components necessary for both high data-rate communications and advanced-resolution radar imaging applications.

Bottleneck

The new integrated circuits tackle data bottleneck issues for mobile communications applications and enable radar-imaging technology to be scaled down to the size of a computer laptop, the company said.

According to IBM, advanced radio frequency integration has been a key driver in the rapid growth of mobile device capability and sophistication. Millimetre-wave bandwidth has the ability to support gigabit per second (Gb/s) wireless communications, dramatically expanding opportunities for mobile backhaul, small cell infrastructure, and data centre overlay network deployment.

Millimetre-wave spans 30 GHz to 300 GHz on the electromagnetic spectrum – 10 to 100 times higher than the frequencies used for mobile phones and Wi-Fi. Frequencies in the range of 90-94GHz are well suited for short and long range, high-resolution radar imaging – due to their short wavelength, relatively low atmospheric attenuation, and ability to penetrate debris, IBM said.

Indeed, IBM says scaled down radar technology improves pilots’ ability to penetrate fog, dust and other vision impairing obstructions. Moreover, the design’s support for two antenna polarisations – with minimal increase in footprint – provides a further advantage while navigating through fog and rain, IBM said.

“This transceiver presents the highest level of integration achieved so far in a silicon-based solution for millimetre-wave frequency applications,” said Dr. Alberto Valdes-Garcia, a researcher in the Communication and Computation Subsystems Group in IBM Research, in a statement. “It is a key step toward phased-array systems of the future that are scalable, low-volume, lightweight, and low-cost.”

Tiled packaging

The packaged transceiver operates at frequencies in the range of 90-94GHz and is implemented as a unit tile, integrating the aforementioned four phased array ICs and 64 dual-polarised antennas.

By tiling packages next to one another on a circuit board, scalable phased arrays of large aperture can be created while maintaining uniform antenna element spacing. The beamforming capabilities enabled by hundreds of antenna elements will allow for communications and radar imaging applications that will extend over a range of kilometres.

Each of the four phased-array ICs in a tile integrates 32 receive and 16 transmit elements with dual outputs to support 16 dual polarised antennas, IBM said. Multiple operating modes are supported, including the simultaneous reception of horizontal and vertical polarisations.

Fabricated using an advanced IBM silicon-germanium (SiGe) semiconductor process, the ICs also integrate frequency synthesis and conversion as well as digital control functions.

The complete scalable system, which includes antennas, packaging, and transceiver ICs, transforms signals between millimetre-wave and baseband, all in a form factor smaller than a 20p coin, IBM said.

Mobile service providers have started to alleviate backhaul congestion issues by using E-band wireless links. E-Band spectrum, allocated by the FCC for point-to-point communications, covers frequencies in the range of 71-76 GHz, 81-86 GHz and 92-95 GHz, and enables wireless data transfer at very high rates.

Low atmospheric attenuation

The atmospheric attenuation in this band is relatively low, making it well suited for supporting long-range communications links. IBM officials noted that today’s E-band solutions consist of multi-chip modules and bulky mechanically aligned antennas.

The newly developed compact scalable phased array solution provides electronic beam steering and the bandwidth to support Gb/s wireless communications.

IBM debuted the phased-array transceiver design at the IEEE Radio Frequency Integrated Circuit Symposium in Seattle on 4 June.

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Originally published on eWeek.