How do the new Panasonic Cyclonic Wave Microwave Ovens work and are they better than ordinary microwave ovens?
I just did a quick check of the patent literature to see if I can figure out what those new Panasonic ovens are doing differently. I found an international patent application WO 2009011111 A1 and 5 national applications, including US 20100176123 A1. Assuming that these patent applications describe the new microwave ovens, they look interesting.
One of the basic problems with microwave cooking is that the microwaves reflect from the metal walls of the cooking chamber and establish a standing wave pattern. Standing waves appear whenever vibrations are confined to limited region of space, such as in musical instruments on the surface of water in your drinking glass. The vibrations “dance in place,” which is why they’re called standing waves. In some places, the motion of a standing wave is strong and in other places, it’s weak.
The standing waves that form in a microwave oven’s cooking chamber aren’t vibrations; they’re electromagnetic standing waves. Nonetheless, they have that same characteristic of having more intensity in some places than in others. Those variations in microwave intensity produce uneven cooking and are thus a nuisance. Two conventional solutions to the uneven cooking problem are to move the food about, typically on a rotating platform, or “stirring” the microwaves with moving metal objects that dither the standing waves about.
What Panasonic appears to have done is develop a more sophisticated microwave source, one that can steer the microwaves as they first enter the cooking chamber. The technique they’re using is similar to that used in phased-array radar; both devices steer their microwave emissions by adjusting the relative phases of their many emitting antennas. If they swirl the emitted wave around rapidly, calling it a “cyclonic wave” would seem appropriate.
By changing that microwave steering rapidly, the Panasonic oven can vary the standing wave pattern inside the cooking chamber so that each region of space has approximately the same average microwave intensity. Food should therefore cook relatively evenly in this oven.
The approach makes sense and should be effective. As to whether the technique is cost effective and how it compares to the other techniques for improving the uniformity of cooking, that’s beyond what I can predict myself.