Click here to go to our page on microwave ovens
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Click here to go to our page on microwave auditoy effects
Click here to go to our page on the biological effects of electromagnetic radiation
Click here to go to our magnetron page (learn how a magnetron works!)
Click here to go to a page on microwave toilets
Click here to learn about medical applications for microwaves
How to test a microwave oven
The RF & Microwave Research Group (RFM) here does some interesting work on microwave heating, among other things.
http://www.ljmu.ac.uk/BLT/BEST/RFM/
Besides cooking, microwave heating has many industrial uses (drying paint or wood products), and medical applications (cell destruction, sometimes used to treat cancer or other illnesses.) There was recent inventor that wanted to develop a waterless toilet that used microwaves to reduce waste to ashes (click here to learn more). You can even use microwave energy to kill bugs that are infesting cereal grains. One huge market for microwave heating is for medical purposes.
History of Microwave Heating
Is located on this page.
Microwave Ovens
Are located on this page.
What is new in microwave heating?
Directed energy weapons (DEW)
The use of high power microwaves as a weapon is limited only by the imagination. USA Today discusses some of the potential uses, including the "pain ray" and another scheme to melt the guidance systems of missiles aimed at aircraft while they are taking off or landing.
One defense contractor has been working for ten years on what they call the Active Denial System, which is a more marketable term than "pain ray". It uses W-band electromagnetic energy focussed into a narrow beam (think about how much antenna gain you get with a meter dish at 94 GHz). So far, defense customers have NOT lined up to buy this, and DARPA has said "Hell, no"! However, one Los Angeles jail has a remote control version for crowd control, thanks to a grant from the Department of Justice.
In spite of the marketing hype and safeguards to turn off the ray after a few seconds, exposure can be extremely dangerous, as it is actually frying your skin. None of the fielded versions permit the operator to continuously illuminate a subject, for good reason. If it fell into the wrong hands, a good hacker could bypass that "problem" pretty quickly no doubt. If you are a terrorist, you might like to get your hands on this to use as an instrument of torture. But the argument is, why bother, when a $0.99 disposable lighter can do the same thing?
The system that has been filed so far is very expensive. The high power is generated by vacuum electronics gyrotron, which requires a cryo-cooler for its high temperature superconductor (HTS) magnet. It takes hours to cool down, so it must be left on all the time. The system drinks a large tank of fuel every day, or it must be plugged into an electrical panel that can provide copious amounts of AC current, like that special GM Volt car outlet that some rich people have in their garage. You can read about the cooler in this paper which you can find by Googling:
Pulse Tube Cryocooler for Rapid Cooldown of a Superconducting Magnet by M.A. Lewis et al.
Below, Rachel Maddow explains the conops of the pain ray:
If you think you might be in a situation where you might be exposed to the pain ray, what can you do to reduce the effect? Wrapping yourself in aluminum foil is not going to work, as any holes in that "armor" are still in for a burn.
Microwaves101 exclusive theory, remember where you read this! If you study different videos of the pain ray in action, you'll see "show-off" people trying to stand in front of the beam as long as they can. The people that can take the beam the longest are invariably old geezers. Is it because they are such a tough old birds and can handle pain? Not really; it is because their skin is dried out and therefore does not have the dissipative properties of normal skin. So if you want to attack a facility that possesses the pain ray, send your oldest, most dried up comrade to get the job done!
What is the future of the pain ray? The initials FMS come to mind... foreign military sales. If your country won't buy it, other less ethical regimes will. Gotta serve the Raytheon stockholders!
Long ago, Raytheon Company's legal department told us never to mention their good name on this web site, or the penalty might include "termination". Gentlemen, that option is no longer available to you.
Variable frequency microwave (VFM)
Did you ever wonder why doesn't someone invent a microwave oven that doesn't need a stupid turntable to prevent hot spots in your potatoes? Well, it has been done, and it is called variable frequency microwave (VFM). Here the microwave energy is frequency hopped every 5 microseconds or so, to that the pattern of energy distribution is randomized. Don't look for this technology under the Christmas tree yet, it is expensive and therefore relegated to industrial applications such thermal processing of semiconductor wafers.
Microwave drill
Here's some info on a "microwave drill" that works by heating the crap out of anything you want to put a hole in (except metal):
http://www.trnmag.com/Stories/2002/103002/Microwave_drill_melts_concrete_103002.html
Microwave auditory effect
This is related to heating caused by microwaves. Dating back to WWII, people have reported being able to "hear" microwaves. The phenomenon has been studied over the years, and was named the Frey Effect, after one researcher, who is in our Microwave Hall of Fame. Learn more about "MAE" here on Microwaves101.