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Microwave Microelectronics
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20439 |
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Section : |
NATURAL SCIENCE
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| Issue
Date : |
3 / 1992 |
3,174 Words |
| Author
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Mattew Kohler
Matthew Kohler is a research assistant in the Department of
Nuclear Physics at the University of Colorado at Boulder. |
Now you've done it. You're lost. You went into the woods with your copy of Walden because you wanted to get away from it all, and now it looks like it might be permanent. You've got a good map but you've been bushwhacking and without familiar landmarks you can no longer locate yourself. But wait! All you have to do is make a phone call. You reach into your pack and pull out your portable telephone equipped with the latest in microwave integrated circuit technology. You press a few buttons and a microwave signal puts you in contact with an array of satellites, which relay your exact latitude and longitude. So much for getting away from it all. Oh, well, now that you have given in and used your high-tech phone, you might as well give the folks a call….
Before the end of the millennium it is quite likely that no region on the surface of planet earth will be beyond the reach of a portable telephone. Motorola is planning to use microwave integrated circuit technology to construct a global cellular telephone network, which will employ 77 satellites and is scheduled to be operational by 1997. At first, the cost will be prohibitive for most of us, but Motorola expects user costs to drop rapidly as more customers are added to the network.
This audacious vision is becoming a reality thanks to recent advance in mastering the microwave region of the electromagnetic spectrum. Radio and television waves, which readily penetrate most man-made structures, are already being widely exploited for communications purposes. So, too. With fiber optics, the optical waves are being exploited for communications. Yet, between the long wavelength radio and television waves and the much shorter wavelength optical waves are the microwaves, whose potential has until now been under exploited because the technology for manipulating them was primitive.
Microwave technology came into its own during World War II, when the development of radar was a matter of life and death. Early in 1940, British scientists built a special type of vacuum tube called a magnetron that could operate at microwave frequencies. With the magnetron, it was possible to use microwaves rather than radio waves for radar. The higher-frequency, shorter wavelength microwaves could be concentrated into directed beams more easily and were therefore more effective for locating objects.
Since the war, vacuum tubes have been abandoned in most electronics applications in favor of the compact. Reliable, and inexpensive microchip. Radar systems however are only now completing the
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