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Engineers Build Teeny-Tiny Bluetooth Transmitter That Runs On Less Than 1 Milliwatt (ieee.org)
Engineers at the University of Michigan have built the first millimeter-scale stand-alone device that meets Bluetooth Low Energy (BLE) specifications. "Consuming just 0.6 milliwatts during transmission, it would broadcast for 11 years using a typical 5.8-mm coin battery," reports IEEE Spectrum. "Such a millimeter-scale BLE radio would allow these ant-sized sensors to communicate with ordinary equipment, even a smartphone." From the report: The transmitter chip, which debuted last month at IEEE International Solid-State Circuits Conference, had to solve two problems. The first is power consumption, and the second is the size of the antenna. An ordinary transmitter circuit requires a tunable RF oscillator to generate the frequency, a power amplifier to boost its amplitude, and an antenna to radiate the signal. The Michigan team combined the oscillator and the antenna in a way that made the amplifier unnecessary. They called their invention a power oscillator. The key part of an oscillator is the resonant tank circuit: an inductor and a capacitor. Energy sloshes back and forth between the inductor's magnetic field and the capacitor's electric field at a resonant frequency determined by the capacitance and inductance. In the new circuit, the team used the antenna itself as the inductor in the resonant tank. Because it was acting as an inductor, the antenna radiated using changing magnetic field instead of an electric field; that meant it could be more compact.
However, size wasn't the only thing. Quality factor, or Q, is a dimensionless quantity that basically says how efficient your resonator is. As a 14-mm long loop of conductor, the antenna was considerably larger than an on-chip inductor for a millimeter-scale radio could be. That led to a Q was that was about five times what an on-chip inductor would deliver. Though it was a much more efficient solution, in order to meet BLE specifications, the team needed a better way to power the power oscillator. Their solution was to build an on-chip transformer into the circuit that supplies power to it. The transformer looks like two nested coils. One coil is attached to the supply voltage end of the oscillator circuit, and the other is attached to ground side. Pumping the transformer at a frequency twice that of the power amplifier wound up efficiently boosting the flow of power to the antenna.
However, size wasn't the only thing. Quality factor, or Q, is a dimensionless quantity that basically says how efficient your resonator is. As a 14-mm long loop of conductor, the antenna was considerably larger than an on-chip inductor for a millimeter-scale radio could be. That led to a Q was that was about five times what an on-chip inductor would deliver. Though it was a much more efficient solution, in order to meet BLE specifications, the team needed a better way to power the power oscillator. Their solution was to build an on-chip transformer into the circuit that supplies power to it. The transformer looks like two nested coils. One coil is attached to the supply voltage end of the oscillator circuit, and the other is attached to ground side. Pumping the transformer at a frequency twice that of the power amplifier wound up efficiently boosting the flow of power to the antenna.
It *would* run for 11 years off that tiny battery. The key word is "would". The battery will discharge and degrade just as fast, on its own, with no load.
Can you hear me NOW!?!?
FTA: "magnetic field instead of an electric field; that meant it could be more compact".
IIRC an antenna's magnetic field intensity falls off as the cube of distance, whereas the electric field falls off as the square. I'd be interested to know how the range of this new tech compares with a more traditional transmitter having similar output power.
'The Economy' is a giant Ponzi scheme whose most pitiable suckers are the youngest among us and the yet-unborn.
Great. So now we know they can build even smaller little spy toys to listen in on us.
Yes, I am HOSTing cocks and balls at the truck stop... apk
I dunno why these Michigan bros are so excited. I mean, I talked to a homeless guy that told me all about how he had fillings that had microphones, their own power source and wireless transmitter. On top of that, they were installed over a decade ago. Seriously, these guys are behind the curve. ;)
Anons need not reply. Questions end with a question mark.
"They called their invention a power oscillator."
Sounds very much like the way the old regenerative radio receivers worked, if I am not mistaken... Using the antenna as an inductor in the resonator circuit... If the regeneration was cranked up, the receiver turned into a transmitter.
They actually make button cell batteries with different chemistry for long life. Instead of CR2045 for example, I think it is BR2045, or something like that. The regular ones have the properties they do because of the exigencies of economics, NOT the constraints imposed by battery technology, chemistry, or physics.
In fact, most promising technologies reported in the press that never reach production fail not because they cannot work at all or fail to deliver as promised, living up to expectations, but rather they end up economically infeasible for some one reason, or more likely literally dozens of reasons.
Thanks for keeping it scientific, guys.
impersonation != satire/ridicule
Still more stupidity from you. Grow up.
Even more connection issues with Bluetooth. Just what the world needs.
We suffer more in our imagination than in reality. - Seneca
You freak, why are you constantly bragging about your debased activities?