December 8, 2016
GE has spun out a company that threatens to reduce 5G network complexity by a freakish amount, with a novel twist on a device that hasn't seen much of a change in at least 50 years: the electrical switch.
Implemented as a micro electromechanical system (MEMS), the new switches can scale from milliwatts to kilowatts and dissipate phenomenally little heat anywhere along that range. The applications for a cheap, remotely programmable chip-sized switch are almost endless, but two verticals likely to see implementation first are 5G, where it would be used for RF tuning, and the industrial Internet of things (IoT), where it would excel as a high-power circuit breaker.
After that, the company envisions potential applications in battery management, home-automation, electric vehicles, medical instrumentation, wireless base stations and more.
Menlo Micro might be a spinout, but it's hardly a startup. For 12 years, General Electric Co. (NYSE: GE) has been making these MEMS switches and using them, mostly in medical systems.
The key to the switch is a new material, devised by GE metallurgists and semiconductor researchers. Menlo Micro CEO Russ Garcia declined to identify the material, but he said it has very low losses and very low resistance so it doesn't dissipate much heat.
That's one of the characteristics that makes the new switch appealing in RF infrastructure devices -- antennas and base stations and the like -- where relatively large amounts of power are involved.
As the industry progresses through 2G, 3G, 4G and 5G, Garcia noted, every subsequent generation of technology has to be backward compatible with the previous ones. "So we never eliminate any bands; we just add to the bands. Now if you look at a tower or even a metro small cell, the complexity of the radios is substantial. All of those radios need to use as few antennas as possible, so you almost have an RF chain for every set of bands. You may have an infrastructure device with ten, 20, maybe even 50 watts of power or more, and there is no one device that can handle that power or have good enough RF performance that allows you to make tunable filters, or even have band-selectable filters so you can switch from one to the other without too much loss."
Or there wasn't until Menlo Micro devised its switch. It can be used to create tunability in filters and power amps (PA) for that class of equipment, Garcia said.
Handsets are not high-power in comparison, but the technology is germane there too. RF functions in handsets, including antenna selection, antenna tuning and PA switching, are handled by components implemented with silicon on insulator, but SOI ceases to be a practical solution at about 3 GHz, Garcia observed. Meanwhile, there are proposals for 5G that range up to 28 MHz.
Menlo Micro believes its MEMS can be as cost-effective as SOI devices for RF frontends in 5G handsets, but able to handle tuning and switching even at the highest 5G frequencies, all at an order of magnitude greater performance," he said.
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here on Light Reading. Menlo Micro has no inclination to compete with the incumbents in that market, but is evaluating the option of licensing the technology to larger companies. There is potential for developing components and subsystems that simply don't exist today, for example a remotely digitally controlled phase shifter, or having two high-powered tunable duplexers. As a practical matter, what does that mean? "Today, on the tower, if you've got a multi-band cell site, it has phase shifters to do phase alignments across all the different bands. You actually have to tune that with a wrench," Garcia said. "That device changes to something that in the back office you can program the phase shifter to be whatever it's supposed to be by the use of our switches. "And instead of having a filter with a band of operation, you'd be able to create a filter that tunes for every band of operation on its own. It reduces the amount of equipment because you have modular tunable devices, and you don't have to do truck rolls," he said. On the industrial IoT side, the issue is high-power actuation. A lot of the connections and sensors and processors are all low power, but they all may end up having to actuate something -- a circuit breaker, a lamp post, a robotic arm, an HVAC system -- things that might require hundreds of volts and tens of amps to actuate them, Garcia said. "Our device can be in the on-state and would require nanoamps of current to stay on because it's electrostatic, which makes it ideal for industrial IoT," Garcia said. The new material all this is based on can be handled by standard MEMS fabrication facilities. — Brian Santo, Senior Editor, Components, T&M, Light Reading
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