A dielectric polyrod having at least one tapered section, where a section exposed outside of the waveguide is tapered a long a curve that depends on the dielectric constant of the material used. The invention also relates to an aperture matched polyrod antenna which includes the same and an inductive tuning element used to achieve wideband impedance match and to create a Gaussian beam in the radiating near field of the antenna, suitable to mimic a small region plane wave.