Worldwide, there are hundreds of millions of microwave ovens in kitchens, offices and laboratories, each with a magnetron that creates communications problems ranging from an aggravating crackle during a friendly telephone call, to the disruption of 911 calls and the flow of data in wireless computer networks.
Although these effects are difficult to quantify, it's safe to say they're an annoyance, an economic drain and potentially life-threatening.
The basic difficulty is that microwave ovens operate at a frequency near 2.45 GHz – about the same frequency at which telephones and wireless computers operate. In the microwave oven there are two magnets, one at each end of the magnetron. In an amazingly simple discovery, University of Michigan College of Engineering Professor Ronald Gilgenbach and a research team composed of Professor Y.Y. Lau and graduate student, Bogdan Neculaes, all from the department of Nuclear Engineering and Radiological Sciences, found that when they added four permanent magnets to the outside of one of the standard magnets, they could disrupt the magnetic field in such a way that it becomes benign to nearby electrical devices, yet doesn't significantly affect the performance of the microwave oven.
The discovery could also have an enormous impact on the signal-to-noise ratio in radar and in the development of a power source for inexpensive deep-space exploration, and advanced electroporation for highly improved cancer treatment.
ABOUT THE UNIVERSITY OF MICHIGAN COLLEGE OF ENGINEERING
Celebrating its 150th anniversary this year, the University of Michigan College of Engineering is consistently ranked among the top engineering schools in the world. The College is composed of 11 academic departments: aerospace engineering; atmospheric, oceanic and space sciences; biomedical engineering; chemical engineering; civil and environmental engineering; electrical engineering and computer science; industrial and operations engineering; materials science and engineering; mechanical engineering; naval architecture and marine engineering; and nuclear engineering and radiological sciences. Each year the college enrolls over 7,000 undergraduate and graduate students and grants about 1,200 undergraduate degrees and 800 masters and doctoral degrees. To learn more, please visit our Web site at www.engin.umich.edu.
Journal
Applied Physics Letters