PURPOSE: To receive a desired circular polarized wave effectively without receiving an unnecessary elliptic polarized wave by using a feeding circuit consisting of two hybrids and phase shifters in combination and a finite-length reflector plate and a couple of half-wavelength dipole antenna elements for feeding.

CONSTITUTION: A feeding antenna 1 has the infinite-length reflector plate 2 and half-wavelength dipole antennas 3, and the feeding circuit consists of a phase shifter 5, a hybrid 6 for giving each antenna element 3 excitation amplitude, a phase shifter 7, and a hybrid 8. In this constitution, the phase shifters 5 and 7 are adjusted to obtain a desired exciting current amplitude ratio and a phase difference, so an optional polarized wave which has a desired axis ratio is radiated in a freely specified direction. Further, a disturbing elliptic polarized wave and an orthogonal polarized wave are synthesized in the specified direction to suppress the unnecessary sea-surface reflected wave. Furthermore, the feeding antenna elements 3 are arrayed as the feeding antennas, so the axis ratios realize the characteristics which are greatly different in the direction of the desired circular polarized wave and in the direction of the unnecessary disturbing elliptic polarized wave.