Abstract: A coaxial cavity antenna including a cylindrical inner conductor sized for propagation of electromagnetic signals in a preselected frequency range. The coaxial antenna also includes a cylindrical outer conductor positioned coaxial with the inner conductor, and having a diameter larger than the inner conductor. The outer conductor has an aperture ring disposed at an end of the outer conductor. The outer conductor is positioned with respect to the inner conductor to form a cavity between the inner conductor and the outer conductor. The cavity is sized for propagating electromagnetic signals in the preselected frequency range. The coaxial cavity antenna also includes a plurality of aperture teeth radially oriented and disposed around the aperture ring, and an iris ring positioned inside the cavity at a predetermined distance from the aperture ring.