How do frequency selective surfaces work?


Being an electrical engineering student, frequency selective surfaces have interested me but I’m not exactly sure how they are able to block the signals. When I search online I only find very technical explanations, but I want to know how they work on a fundamental level. Thanks

In: Technology

EM waves have an amplitude and a frequency. The atoms in a frequency selective surface are placed such that a wave of particular amplitude and frequency is guaranteed to run into and be deflected by the surface. Since all radiation is traveling at the speed of light, this variable doesn’t have to be accounted for.

For a simple example, look at microwave oven doors: EM radiation in the visible spectrum can get through the holes, but microwaves are the right size to not fit through the holes because of their amplitude and frequency of oscillation while traveling at the speed of light.