What is meant by antenna bandwidth?

Antenna bandwidth refers to the specific range of frequencies where an antenna maintains an acceptable Standing Wave Ratio (SWR) and radiates efficiently. If you operate outside this specific frequency range, the SWR rises, reflected power increases, and the antenna no longer performs well. Distractors referring to angles between half-power points describe 'beamwidth', which is a spatial measurement of the antenna's radiation pattern, not its frequency capability. Similarly, physical dimensions like length divided by the number of elements are nonsense formulas entirely unrelated to electrical bandwidth. Understanding bandwidth is critical because transmitting too far outside an antenna's designed frequency range can damage a radio's final amplifier stage due to high SWR.