Frequency agile resonant cavity antenna

The invention relates to a frequency agile resonant cavity antenna. The frequency agile resonant cavity antenna comprises a main feed source, a parasitic feed source, a reflection coating, a floor anda high-impedance surface. The reflection coating is arranged on the upper portion, the floor and the high-impedance surface are arranged on the lower portion and form a cavity structure, the main feed source is printed on the high-impedance surface, and the parasitic feed source is arranged in the cavity. The reflection coating is a Rogers4003C dielectric plate, and a periodic square metal patchprinted below the dielectric plate enables the dielectric plate to have the capability of partially reflecting electromagnetic waves; the main feed source is a square patch antenna fed by a coaxial probe; the parasitic feed source is a square patch antenna printed below the dielectric plate with the dielectric constant of 2.2; the high-impedance surface is a Rogers4003C dielectric plate, and a periodic frequency agility un