Modeling of the antenna of a satellite system for transmitting and receiving digital microwave signals has been carried out. It was revealed that the shape of the convex antenna master surface strongly affects its characteristics. From the results obtained, it was concluded that the frequency shift of the main radiation is most affected by bending in the vertical plane. In the horizontal plane, this effect is observed only with a very large bending of the driving surface. In addition to the fundamental frequency, the frequencies of side resonances are also subject to displacement. The possibility of creating a small-sized broadband X-band antenna with a bandwidth of about 40–45% is shown. This antenna can be used as an integral part of a phased antenna array.