This paper presents design and development of a compact wideband waveguide polarizer for X-band satellite communication (SATCOM) applications. The polarizer has been designed based on the antiphase posts separated by finite distance in a circular waveguide. The posts have variable height in the waveguide. The polarizer has been analyzed using 3D EM software, and a prototype is fabricated and measured. The measured axial ratio (AR) of less than 1.15 dB in the required frequency of operation is 7.25–8.4 GHz; however, it has 3-dB AR bandwidth of 37.2% over the frequency band of 6.26–9.16 GHz, and return loss is better than − 27 dB required frequency band of operation while it has more than 38% return loss bandwidth (6.25–9.20 GHz).