Nice color photo in Aviation Week shows them mounting the Raytheon APF-79(V) 4 phased radar in the nose of the F16. The array elements are gallium nitride which yields more power than the older gallium arsenide technology. A phased array can generate a good tight radar beam. If all the array elements are excited simultaneously, the beam goes out straight ahead. If array elements on one side are excited a little bit earlier than elements on the other side, the beam goes out angled toward the early side. Some trigonometry will show that the beam can be steered thru 90 degrees, which is about as good as the older technology could mechanically scan a parabolic antenna. Major benny of the phased array is speed of scan. The beam can be deflected from hard over left to hard over right in a millisecond. It is fast enough to track multiple targets.
The accompanied write up skipped a few things that I would have liked to know. How much power can the new gallium nitride elements deliver? The airborne radar I used to work on used a cavity magnetron to generate 50 kilowatts of X-band (10,000 MHz) power. That radar could reach out 200 miles. I don’t expect a single gallium nitride element to generate that kind of power, but I sure would like to know how much power all the elements in the phased array can generate.
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