While avoiding radiation is impossible, there are natural and man-made barriers around us that can reduce the intensity of RF radiation.
An example of a natural barrier is stones, rocks, and dense foliage. You've probably experienced loss of cell phone reception when you've been in or near the woods. That's because trees, shrubs, and almost any kind of foliage pick up cellular signals.
Aluminum foil, sheet metal, and other conductive metals such as copper and silver can reflect and absorb radio waves, interfering with their transmission. We consider them to be man-made obstacles. The higher the conductivity of metals, the better they are at shielding the dominant wave (RF).
