We revisit the radiation characteristics of a dielectric-filled edge-s
lot (DFES) antenna, which is made by circumferentially removing the ou
ter conductor of a coaxial line. The Fourier transform and the mode-ma
tching technique are utilized to obtain a new solution in a fast conve
rging series. A dominant-mode solution for the reflected power and the
radiation field is given in a simple form. The numerical investigatio
n is performed to show the behavior of the antenna input impedance and
the radiation pattern.