In this study, we suggested a waveguide antenna for low-orbit satellite TC&R with hemispherical coverage in the X-band of 7.0~8.5 GHz required for the telemetry command system (Telemetry, Command, Ranging, hereinafter TC&R) for communication between the satellite and the ground station. The proposed antenna is designed using a septum structure inside the waveguide to generate a circularly polarized wave and expand the axial bandwidth. In addition, to extend the beam width of the radiation pattern within the range of maintaining the circularly polarized wave, an outer wall of a corrugated structure was added and offset at the end of the opening of the spherical waveguide. Consequently, the hemispherical coverage characteristics were satisfied, and an axial ratio of around 10 dB was obtained at ±90°. In addition, the average gain of all angles within the beam width at the resonant frequency was −2.9 dBi. Accordingly, sufficient beam width, axial ratio, and gain were secured as antennas for low-orbit satellite TC&R.