Friday, April 6, 2012

Phased Array on a Chip...

Holy silicon wafers, Batman!  A collaboration between UCSD and TowerJazz has produced a working phased-array radar on a single silicon chip.  The chip is roughly a quarter inch on a side, and contains the entire radar: transmitters, amplifiers, phase shifters, and 16 (4 x 4) antenna elements.  It operates at 110 GHz.  Absolutely awesome! 

With just 16 elements, its directional gain won't be spectacular – but this is a lab experiment, a demonstration of concept.  It's not hard to predict that we'll see much larger arrays in short order, with correspondingly higher gains.

Almost 40 years ago, I was floating around on the ocean on an experimental platform for phased array radars.  The platform was the USS Long Beach (CGN-9), a nuclear powered cruiser.  It carried two phased array radars: the AN/SPS-32 and the AN/SPS-33.  These radars were huge, as you can see on the preceding link, which shows the big, flat antenna panels on the USS Enterprise (it had the identical pair of radars).  If I remember correctly, the AN/SPS-33 panels were each 20 feet wide by 25 feet high!  The electronics that drove those antennas filled an entire deck (story) of the superstructure, and took dozens of men to care and feed it.  I'd estimate that on the cruises I participated in, the AN/SPS-33 (which I worked on) was “up” (operational) less than 10% of the time.  Why so unreliable?  Mainly the sheer number of discrete systems, subsystems, parts, wires, etc. that all had to be perfectly functional for it to work.  All this on a ship rolling around in an atmosphere full of corrosive salt.

It's remarkable to read that this system that occupied perhaps 700 cubic yards has been shrunk to something smaller than a postage stamp...

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