What is the Brewster Angle?
The Pseudo-Brewster Angle (PBA) is the angle at which the reflected TM wave (from a flat earth or water surface) is 90 degrees out of phase and minimum amplitude with respect to the direct wave. “Pseudo” is used here because the RF effect is similar to the optical effect from which the term gets its name. Above this angle, the reflected signal is in-phase with the direct signal. Below this angle, the reflected wave is between 90 and 180 degrees out of phase with the direct wave. Some degree of cancellation takes place in either condition, depending upon the difference between the lengths of the direct path and the reflected path. The largest amount of cancellation occurs near zero degrees, and steadily less cancellation occurs as the PBA is approached from below.
