This paper presents the capacity of an S band circularly polarized patch antenna using a ferrite material for low-earth orbiting satellites (2025–2100 MHz for TeleCommand) to obtain a semi-isotropic radiation pattern. Indeed, circularly polarized antennas are generally large and bulky which is often incompatible for spatial applications especially for small satellites. A new antenna design is proposed with the following maximum dimensions: a diameter of 80 mm and a height of 12 mm. The structure presents an axial ratio lower than 6 dB (according to requirements) and a realized gain higher than −6 dB over a 4% bandwidth at the limit of coverage i.e. 90° irrespective of the azimuth angle (φ).
