A switched beam antenna array based on substrate integrated waveguide (SIW) technology is designed and simulated for 60 GHz communications. The antenna array is fed by 4×4 planar butler matrix network in order to achieve the switched beam characteristic. The use of SIW technology offers a low cost and a planar design. Each of the components is designed and verified through simulations in electromagnetic field simulation tool, CST MWS. The components are integrated later to form the switched beam antenna array. The return losses and isolations are lower than -10 dB from 57 GHz to 64 GHz for all of the input ports. The peak gain for the switched beam antenna array is 16 dBi at 60 GHz.