Trajectory, Propagation Time, and Velocity of Field Energy Flow Near Receiving Dipole Antennas

In antenna theory, a full understanding of both transmitting and receiving characteristics is essential. While many studies have investigated field energy propagation and flow velocity near transmitting antennas, there is a distinct lack of similar studies on receiving antennas. The Poynting streamline method can be used to visually plot the field energy trajectory of a receiving antenna from the far field to the near-field region. The visual representation distinguishes between Poynting streamlines absorbed by the antenna load and Poynting streamlines bypassing the antenna, allowing analysis of the trajectory, propagation time, and velocity of field energy flow near the antenna. In this letter, it is found that due to the reactive field near the receiving dipole antenna, the velocity of the field energy flow near the antenna is slower than the speed of light. Despite the variation in trajectory length, the propagation time of the field energy flowing along the Poynting streamline, all of which terminates at the antenna load, exhibits approximate uniformity.