Feedforward antenna is also called centre focus antenna or Prime focus antenna, what is we often call "big pan". Feed locates the focus point of the parabolic antenna, Satellite signals are reflected by the antenna parabolic surface, and then these signals are focused on the feed. Generally feedforward antennas present roundness, and some present squareness, whose structures are simple. For this kind of antenna, it is convenient to do the installation and adjust the feed, so generally the diameter is within 4 meter. The diameter of common roundness feedforward Rx antenna is 1.0m,1.2m,1.35m,1.5m,1.65m,1.8m,2.1m,2.4m,3.7m,4.2m,and so on, which are often used for C-band signals.

According to the antenna fixing types, roundness feedforward Rx antenna is classified into two types, which are ground mount type and kingpost type. As shown in Fig.2-2.