Friday, October 14, 2016

electromagnetism - How do electromagnetic waves travel away from an antenna?


I have heard that in an antenna the electrons move back and forth and create an electric field which varies with time. This varying electric field in turn, creates a varying magnetic field. These two varying fields together create an electromagnetic wave.


How do these waves travel out from the antenna?


If the electrons are moving back and forth vertically, wouldn't there only be an electromagnetic wave near the antenna? What makes them spread out or expand?





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