A circular polarization patch antenna operating at S-band is proposed which is complaint with a large curvature column structure. The coupling effects between the conformed antenna and the based structure are considered accurately in the refined simulation models and impedance performance has been illustrated in the paper. The designed maximal gain in the normal direction of the antenna aperture reaches 7 dBi possessing the polarization axial ratio from 0.3 dB to 3.2 dB within ±45◦ scanning volume.