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Radar/Wireless Transmitter on a Chip
dganapa writes "Researchers at the California Institute of Technology, headed by Dr. Ali Hajimiri, have developed a low-cost radar system on a silicon chip. The entire system has been designed from the ground up on silicon, thus leading to reduced cost as well as robustness in response to design variations and changes in environment. The chip runs at a staggering speed of24 GHz (enabling it to transfer data as fast as the main network of the Internet) and can soon lift wireless, high-frequency communication to a whole new level. The radar as such is not as powerful as a conventional radar but because of its cost-effectiveness, a number of them can be coupled together to perform really well. A related NY Times article is here. A recent article from Slashdot shows that radar technology is increasingly being implemented in the automobile industry. This current chip is sure to be much more successful than its predecessors as far as the automobile industry is concerned, but whether or not its processing speed will become important in the computer industry remains to be seen."
The chip runs at a staggering speed of24 GHz (enabling it to transfer data as fast as the main network of the Internet)
How many Libraries of Congress is that?
Imagine a beowulf... oh nevermind. :)
My Greasemonkey scripts for Digg &
(yes - of course we can disable it if we want to)
but wouldn't it be great to have the brakes applied if you lose attention for that one split second. Everyone I've known who has been in a car accident, (luckily they were minor) has said just that.
Unless you are James Bond, or just want to do some fancy driving a radar controlled braking system would be great.
You can't expect to wield supreme executive power, just because some watery tart threw a sword at you
Why can't I get my liquid nitrogen cooled 24 Ghz ahtlon64 then? I thought we weren't capable of making gates that would switch that fast?
Can someone clear up my confusion?
TODO: 753) write sig.
... and no I haven't read the article yet.
can an array of these be used to emulate a synthetic apreture radar, meaning that a flat panel gives you a 120 to 180 degree field of view from that panel?
Can the processing power of the chips be used to provide an improved image of what is reflecting in the spectrum the radar is working in? With a two dimensional array of 5 by 5 chips, distributed over a 1 foot by 1 foot surface, you could have a 3 dimensional "image" with a resolution similar to a human's 2 eyes. If the chips themselves can be programmed to do the interpolation, you could use a seprate computer to provide a opengl real time image of the world.
Perhaps I should read the article...
-Rusty
You never know...
This same technology could be used for low-cost RFID scanners. If manufacturers can bundle an entire RFID interrogator on a silicon chip, it would reduce scanner costs and accelerate RFID adoption. The low power of this silicon-based GHz RF would be acceptable in many RFID scanning applications.
Two wrongs don't make a right, but three lefts do.
... having radar in your car. Just don't be surprised one the police finds a way to screw you over for a few more bucks by using passive radar to determine your speed.
Hate me!
* The chip could serve as the brains inside a robot capable of vacuuming your house. While such appliances now exist, a vacuum using Hajimiri's chip as its brain would clean without constantly bumping into everything, have the sense to stay out of your way, and never suck up the family cat.
Not really. The radar might reflect off the cat or your leg, but would pass right through wooden furniture and walls. A radar-equipped vacuum cleaner would still bump into stuff.
* A chip the size of a thumbnail could be placed on the roof of your house, replacing the bulky satellite dish or the cable connections for your DSL. Your picture could be sharper, and your downloads lightning fast.
Wrong on size. Satellite dishes are big to both help collect enough RF energy to get a clean signal and to pinpoint on a single satellite. Without the needed collecting area and beam-forming span of the antenna, the signal would be weak and overlaid with signals from other satellites in orbit.
Two wrongs don't make a right, but three lefts do.
Is the frequency band at 24 GHz actually licensed for automotive radar systems?
According to this press release it's not licensed in parts of Europe.
And in the US, there is only a temporary license.
I haven't found an unbiased summary yet - the referenced press release is from a working group of companies in the automotive industry.
This summary says that the frequence is reserved for radio astronomy and similar users.
This will make those radar detectors (used to detect police radars in speed traps) virtually useless. Once every car is equipped with a radar, these detectors will beep continuously.
Maybe they can be replaced with very sensitive tri-sensor devices that test for a specific combination of: doughnuts, coffee, and bacon.
If my early morning math is right the wave length of 24Ghz is about half an inch. Does that mean that the chip could distinguish distances as small as half an inch?
That would be really cool for a small robot if it could.
A related NY Times article is here.
"You should never doubt what nobody is sure about." -- Willy Wonka
Just guessing: The radar signal is generated by a microwave oscillator formed by some kind of folded structure on the silicon. The structure must be folded because it must be at least one wavelength of the generated frequency. The wavelength of a 24 GigaHertz signal is:
(300,000,000 meters/second [the speed of light, approx.]) / (24,000,000,000 cycles/second [24 GHz]) = 0.0125 meters, or a wavelength of 1.25 centimeters.
In photos, the radar chips are shown to be less than 1.25 centimeters in width and length. That makes me guess that there is some folded resonant structure.
Does anyone know if that assumption is correct? Is it possible to generate a signal from a structure smaller than one wavelength?
One of the articles says that the maximum transmission speed is 1 GHz, so that is the maximum speed of any digital or analog circuitry. The governmentally designated band is 22 to 29 GigaHertz, so the theoretical maximum speed of data transmission is 7 Gigahertz, the width of the frequency band.
This is a major breakthrough. A large number of these chips can be combined with digital signal processing to make a radar that has an effective antenna size much larger than each chip. Large effective antenna sizes are also great for reliable directed data transmission.
The chip is neat, but the article is very heavy on the hype. The only new thing here is putting everything including the antenna on one chip.
And conventional radars do not cost "millions of dollars".
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
I found the NYTimes article dumbed things down a little too much. Basically, this is a press release by a fairly young professor about a ISSCC paper to be presented next week.
CMOS is getting fast enough (could be SiGe BiCMOS chip but probably CMOS) to allow for amplifiers and ADC (analog-to-digital) that work in the radar (~25GHz on up) range & also allows for million gate DSPs and digital logic on the same chip. The analog front-end is running around 24GHz which gives a 1/4 wavelength around 3mm (antennas are implemented as PCB traces off-chip). This is an analog GHz signal where the transistors are amplifying a tiny GHz signal using analog amplifiers. Digital clock speeds are completely different. Digital is like switching completely from off to on (ie. 0 to 5V -- in reality try 2V or 3.3V). This is like a uV signal being amplified to be later converted to a digital signal with a more reasonable bandwidth that a digital CPU could handle (like your overclocked Pentium).
The parallel analog antennas & blocks which allows for parallel ADC of 8 channels.. 8 parallel radar antennas. By using parallel processing you can use the information gained by the other channels to improve your ADC or have each channel only need to work at 1/8 of the total speed. Also, having 8 antennas allows phased arrays where you can control the beam and allows you to scan the beam or block out other signals (much like cell towers can focus in on one cell signal, and why your 802.11 router has two antennas). So, depending on how much bandwidth the ADCs need & how fast the DSP is running is really the 'digital' GHz part of the chip. So the digital processing is probably a more reasonable 100's of MHz (though hard to compare DSP speed to CPU speed). The processed digital waveform can be sent high-speed off chip, or to on-chip CPU to be used to disable your cruise-control and hit the brakes for you.
Why do you care? Well by using straight CMOS the radar system can be made on one chip and not need 'exotic' GaAs/SiGe/InP (BJTs of traditional radar systems) and when the automotive chips get down to sub-$5 they will show up in every car. Also doing it this way, much smaller power is involved and you don't need circuits that look like your microwave oven waveguides.
Imagine placing these chips on top of light poles every 1/2 mile on big city highways. Now enable them to relay information to each other and broadcast it via Bluetooth or something like that.
In your car have a GPS map that has wireless capability to these units. You can get a real-time traffic density map of the city and decide if you want to take the freeway home or take another route...
Seems like a pretty easy app to set up also.
"In like 5 years they'll like have software that can download movies." Lars Ulrich, Metallica
As someone who volunteers at his car club's high-speed driver education events and has attended one of the events as a student- um, no.
First, braking is NOT always the best choice. When you're doing 60 and a moose jumps out in front of you, you STEER, not BRAKE. Why? Because under about 200 feet, you're never going to stop in time but you probably can change lanes. Simple physics tell you why- it's a lot easier to accelerate a car enough to move 10 feet to the side than it is to bring the whole thing to a stop.
Second, when said moose jumps out in front of you, steering while braking is exactly what causes many accidents, because you unbalance the car, shift a huge amount of weight to one corner tire, which becomes drastically deformed under the weight and becomes nearly useless; meanwhile, there's next to no weight on any of the other tires, and they're useless too. Your tires have what is called a "friction circle"; draw an X-Y axis, now a circle centered. That describes how much acceleration your tire can accomplish in any one direction. Notice that there's less of any one particular axis when you're doing both? Your tires always stop better when you're not trying to steer, and vise-versa. Both controls should ALWAYS remain under control of the driver so the system doesn't try to do something while you're doing something else.
Third, proper driver education is a lot cheaper(just one $200-300 event, depending on the club, will teach you quite a bit about how to handle your car properly) in the long run.
Your friends who have been in accidents need to analyze WHY they got into the accidents they did. I'm guessing an automatic braking system would not have "fixed" any of this, but better attentiveness, good judgment, and proper knowledge of how to handle their car would have.
Please help metamoderate.
It could be a component, but only one piece. The really tough part if creating the software that intelligently drives. There are so many oddball cases you have to deal with in driving that it will be a very long time before this is possible.
I don't think the goal is that loft at this point - we're talking about an aid for the (human) driver to see through fog.
Quoted from the first line of the article:
Imagine driving down a twisty mountain road on a dark foggy night. Visibility is near-zero, yet you still can see clearly. Not through your windshield, but via an image on a screen in front of you.
This would be nearly impossible to implement by radar alone, but this is a step towards it.
The problem, of course, is clutter. Fog, snow and rain all obscure your view through radar because of clutter and attenuation. Even with a very intelligent algorithm combining the skills of hundreds of experienced mariners, finding the sweet spot on the clutter and gain controls is difficult.
Another issue is "obstructions" which won't cause an echo at all - like the very big fall waiting for you on the other side of the missing guardrail.
Let's consider a worst-case scenario. It's raining. The gain and clutter are configured to give you a clear view of cars in front of you, guardrails, concrete obstructions, rocks, etc despite the driving rain.
A few minutes ago, a truck drove down the road and a forklift pallet of toilet paper fell off the truck. Do you think your radar is going to show you its echo? I think its relatively weak echo will be filtered out as clutter...
How about something more substantial, a big square rooftop HVAC unit sitting on the road, one of its four corners pointed directly at you? Even under the best possible circumstances, it's going to be very hard to get an echo off that, since there isn't a surface normal to the RF energy leaving your car...
Or a kid, wandering around the road. Daddy had an accident because he trusted too much in his automotive radar system, and has been hurt. The clutter on your own radar system is set high enough to obsure the echoes from the water droplets of the driving rainstorm. Now, what kind of echo are we going to get off a human being, considering that we're mostly water?
I've seen people on radar systems. You really don't see much, and I don't care whether it's X-band or S-band, a crappy little Furuno bought at the yacht club or a $200,000 interswitched Lloyds type-approved Racal-Decca ARPA radar used on an aircraft carrier. You're still not gonna see much of a target.
While I was designing radar video systems for Litton (before the tech collapse), we had constant reports that bridge crews were using the radar for navigation, rather than properly sighting, having crew on watch, and bringing the ship to a slow speed with due consideration of conditions.
The ship's captain probably has 20 years experience at sea, and is now in charge of a multi-million dollar vehicle with many lives on board. These are responsible, intelligent and experienced people. And they often take their radar's accuracy for granted.
How, then, are we going to get Joe Sixpack who currently thinks nothing of driving around in his SUV, cellphone planted to his ear, to understand that the radar image presented to him is NOT infallible? That it is, despite its ability to "see" through fog, snow and rain, actually less accurate than the human eye?
Hell, how are we even going to teach him to read the display? With several years of experience reading PPI radar displays, there's no way in hell that I would ever try to use it (or just a quadrant sweep) to drive a car. It's just not as intuitive as it would seem, and I can't even begin to imagine what sort of work would be required to try to create something like a TV picture of the road ahead.
First off, to scan the image, the transceiver's antenna would have to be scanned - physically moved around - at the same speed as the desired refresh rate of the
Fire and Meat. Yummy.
I didn't see anything in the article that referred to power output - maybe I just missed it. But I think that there may be lots of applications where the kind of power you are thinking about isn.t needed, Military units need maximum range, and range is often hundreds of miles. But to spot another car in the fog all you need is a hundred yards or so.
And the beam-focusing aspect means that 100 mW can go a long way.
I was thinking that the communications aspect may be the big payoff, think what this would do for a cell-phone. No external antenna, and the comm beam always aimed in a direction other than the user's head. Cuts the radiation exposure by orders of magnitude. Of course you might not want to step in from of one...
To hear the gods laugh tell them your plans.
I know everyone is excited about the chip that uses almost no power to act as a radar. However, unless they re-write a few laws of physics, I thought the range of a radio signal was dependent upon its power with a few other environmental factors thrown in. Did I miss something, or has no one stated the range of this device yet?
It's all about the power with radar. So, it's unlikely that a chip that actually manages to get in the right bandwidth to work as radar with the available power it has available is going to have much output below that optimum. I would bet they are using whatever frequency that sits on top of the bell curve, and are happy to have it.
...
Transmit; listen; figure out the difference between what you heard and what you should have heard if it went on indefinitely (ie no relfection). Repeat, very quickly.
The listening part is already at it's limit as to finding small reflections, though, they're already a very, very small fraction of your transmitting power. That's where all the computing is taking place, where you put the software resources.
You mentioned harmonics; I think you misunderstand them a bit. They don't go both ways from the original frequency. You must listen at the same frequency as you transmit; if you listen at a harmonic above that frequency you might hear something at a much reduced level; if you listen at anything below your fundamental frequency (the transmit one) you hear
Nothing.
There is no such thing as a harmonic below the fundamental.
Lowering the frequency in the transmitter means you need more power and it probably won't fit on a chip. If somehow you did try it with an existing chip, all that happens is you get even smaller levels of bounced signal power (you're transmitting less level because you're below the transmitter's optimum) which means even more difficulty listening for reflections.
By the way, diffusing reflections and therefore making an even smaller percentage of them bounce back to the reciever pretty much sums up the whole working theory behind stealth. If you think about it, each attempt to reduce your available reflected signal numbers and strength is like building stealth into your radar. That's like deliberately building bugs into your debugger.
Since virtually all (1) radar systems that can see more than a few metres still require large vacuum tube transmitters to work at all (power, power, power), I'd say this chip is pretty much state-of-the-art and I'd bet they're doing all they can with what we know how to make and what we physically can make right now.
(1) I'd say all (period) but I'm not privy to everything and governments do keep secrets. Perhaps some automotive-types that watch 10 feet for a parked car might be solid state, but so far as the ones I know about, they all still use a small transmitting tube. Solid State transmitters are coming; but this story is really about a breakthrough in making a SS radar at all.
Well, in about 15 years at least...
...At least 15 years in the USA to get all the juristictions on the same page. The way most people drive, this is like money in any Goverments bank that posts a speed limit.
To get a licenced vehicle it will have to have a similar chip in it, pointing at the ground below the car 2 feet from the cars edge. The car will report the speed to you and the cops. No high speed chases, just a ticket or summons in your mail box, maybe it will even triggar an auto-funds-debit (no pun intended.) Forget self driving daydreams, the reason we like to drive is autonomy (again no pun.) Even futuristicly, self driving is a luxury add-on, that this chip might only make slightly less cost prohibitive for general production. As part of an Auto's BlackBox/Lojack system this would be a very, very ecconomical inclusion.
Hmmm, I wonder how many snapshots a digital camera (or bank of cameras) would take in focus with this chip by its side? Entry ways, crowd scaning; can this chip be used in high speed facial reccognition systems?