According to the present invention, provided is a communication apparatus including a radiation source (10) that radiates an electromagnetic wave, and a first phase control plate (11) that is disposed at a position of a distance L1 in a radio wave radiation direction from the radiation source (10). In the first phase control plate (11), a phase of a transmitted electromagnetic wave differs according to a distance from a representative point on the first phase control plate (11). The radiation source (10) is able to supply power up to a position separated from the representative point on the first phase control plate (11) by L1/2.