Posted on 02/28/2004 7:57:31 AM PST by aculeus
The entire functions of a radar system have been squeezed on to a single silicon chip about one fifteenth the size of a penny for the first time.
The miniature system has been created by researchers at the California Institute of Technology in Pasadena, US, who managed to fabricate all the sensing and communications components out of silicon. Their chip is capable of transmitting, receiving and directing high frequency microwaves.
"Until now radar has been a very expensive very large bulky item," says Ian Gresham, an automotive radar engineer at M/A-Com in Lowell, Massachusetts.
Gresham says the radar chip could mean luxury car features - such as radar-controlled parking-aids and obstacle-sensors that make driving in fog safer - could go mainstream because the systems will now cost hundreds rather than thousands of dollars.
If used in communication devices, the chip could also enable lower power, higher bandwidth wireless local area networks (LANs).
"The basic fundamental building blocks behind radar and communications are essentially the same," he explains. Both require the means to send and receive electromagnetic waves and to turn the waves into electrical signals. For radar the waves must be steered so that the size and angle of an object can be determined once it is detected.
Array of antennae
Traditionally, the transceiver that produces and receives the microwaves is steered mechanically with rotating plates. But the reliance on moving parts makes these systems, clumsy and unreliable and forces them to be bulky.
Recently electronically steered systems have been developed consisting of an array of antennae, each one producing an individual microwave signal. The antennae are arranged so their signals interfere to produce a single beam. The beam's angle depends on the relative phases of the contributing signals - by controlling the phase of each signal individually, the beam's angle is controlled without any moving parts.
These systems are more accurate and more reliable than their mechanical counterparts. "But we wanted something really small," says Ali Hajimiri, an electrical engineer at the institute.
"We came up with a completely new set of building blocks and architecture allowing us to do everything in silicon," he explains.
Regulatory hurdles
One example of this was replacing the phase shifter common to electrical transceivers with an oscillator. A phase shifter is a set of components that receives a signal and creates a phase difference by delaying that signal and then outputting it. But an oscillator is simply programmed to produce a signal with the correct phase shift directly - and it can be fabricated on the chip using photolithography.
"The most interesting aspect of this is that it is silicon-based," says Gresham. He says one reason this was possible are the leaps in speed that silicon chip technology has made over the past few decades.
Very high frequency microwaves can now be achieved with silicon. So the radar chip produces at a rate of 24 gigahertz - an order of magnitude more than Intel's state-of-the-art Pentium processor.
However, Gersham warns that there are still regulatory and technological hurdles to jump before mainstream cars and LANs can use the tiny radar system. Regulatory agencies tightly restrict which slices of the spectrum can be reserved for which types of communications, he cautions.
© Copyright Reed Business Information Ltd.
The biggest hurdle is the legal liability problem. Every time the radar fails to prevent an accident (under braking) or contributes to an accident (over braking) the manufacturers will be sued by the trial lawyers. It will require legislation forcing all car manufacturers to install radar while limiting their legal liability, the same as how air bag technology became mainstream.
A great benefit I see to this technology is that some day cars will be able to form virtual trains on the highway, increasing fuel efficiency and highway capacity yet retaining the freedom and low cost of an automobile. We can have trains without the outrageous cost.
Calling all EE types...what would happen if you spread an array of these things across the seam between the windshield and the roof and used a pc for processing....could you get some sort of real time radar imagery, instead of just a warning signal? Something like a SAR mapping feature?
Or should I STFU and get back down on all fours? *grin*
Technology will not erase idiocy.
The Captain:"Readings clear Mr. Sulu. Adjust phase shifters and proceed with passing manuevers."
Mr. Sulu:"Aye aye Captain...lane change commenced. Will overtake and complete manuever in 23 seconds."
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