In mobile microwave communication, reflector antennas have widely been used for very long time. Flat array antennas which have very rigid structure are being used in satellite communication, radar and airborne applications. These antennas are relatively smart in size and have more rigid structure than reflector antennas. The 32×32 elements vertical polarized slotted waveguide flat array antenna is presented in this thesis, The sub-array and feed waveguide network are set up and simulated by 3D-Electromagnetic Software HFSS. This array can have over 4.3% reflection and radiation bandwidth, low side lobe and back lobe. Results show that it has potential application value in radio communication.