Which electrical property is responsible for producing the magnetic field in an antenna?

The property that is responsible for producing the magnetic field in an antenna is current. When an electric current flows through a conductor, it generates a magnetic field around it, according to Ampere's circuital law. This principle is fundamental in antenna theory: as current flows through the antenna, it induces both electric and magnetic fields, which propagate as electromagnetic waves.

The strength and characteristics of the magnetic field are influenced by several factors, including the amount of current flowing through the antenna and its physical configuration. In antennas designed for transmitting or receiving radio frequency signals, current varies with time and creates alternating magnetic fields, enabling radiation of electromagnetic energy into space.

While voltage is involved in creating current, it does not directly generate the magnetic field itself; instead, it is the movement of charge (current) that is essential. Energy and frequency play roles in the overall functioning and efficiency of antenna systems, but they do not produce the magnetic field independently.