English: Animation showing a half-wave dipole antenna receiving power from a radio wave. The half wave dipole consists of two metal rods each one quarter of the wavelength long, attached through a parallel transmission line to a resistance equal to the characteristic impedance of the antenna, representing the receiver. The electromagnetic wave, coming from the right, is represented by its electric field (E, green arrows). The wave's magnetic field is not shown. The oscillating electric field exerts force on the electrons in the antenna rods, creating oscillating currents (black arrows), causing them to travel back and forth between the ends of the antenna rods, charging the ends of the antenna alternately positive (+) and negative (-). Since the antenna is a half-wavelength long at the radio wave's frequency, it excites standing waves of voltage (V, red) and current (I, blue) in the antenna. The voltage and current along the antenna elements is represented graphically by the bands of color; their thickness at any point is proportional to the magnitude of the voltage or current. The waves of radio frequency voltage and current travel down the transmission line and are absorbed in the resistor.