One arrangement to collimate the radiation from a low-gain antenna is a corner reflector. With a conventional half-wave dipole feed orientated parallel to the reflector corner, the radiation is linearly polarized. However, it is also possible to obtain elliptical/circular polarization by rotating the dipole about the reflector’s axis of symmetry.
Greater bandwidth can be obtained by using thicker cylindrical or biconical dipoles for the feed element.
For each combination of reflector width and length, there is an optimum reflector angle and reflector-dipole spacing to maximize the gain. This design given here provides a compact antenna for a given gain or reflector angle.