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. Each of the components is designed and verified through simulations in electromagnetic field simulation tools, CST MWS and HFSS. The components are integrated later to form the switched beam antenna array. The return losses and isolations are better 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 18 dBi at 60 GHz.