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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.
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.
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.
It is indeed possible for a device to generate radio frequency with a wavelength greater than the devices physical size. A typical AM station generates a signal at a wavelength 600 meters to about 200 meters. Most AM stations do not have antennas this long and their transmitter boxes certainly aren't this size.
Frequencies can theorectically be generated with any size circuitry. Im pretty sure this circuit does so using the so called Phase Locked Loop (PLL) circuit, possibly mixing 2 or more together to get the very very very very high frequency by addition. This circuit does not require wire coils (often of relatively large size) to resonate at these "really" high frequencies. There would need to be a filtering step (or two or three) and I can see how this circuit would be hard to miniturize, but I guess they have done it!
Typically for a radio signal to be radiated you need at least a half wavelength antenna but even this can be cheated at. In the microwave region where this device is working at, signals are best radiated using a "dish" type antenna. This chip no doubt does not come with this dish. It simply generates the rf at 24 GHz.
ZBeat
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