Two dimensional microstrip array with high aperture efficiency on FR4 substrate

A novel two-dimensional wideband array of microstrip E shaped patches is designed for use in a 10 % frequency range around the 2.45 GHz ISM band. The main design criterion was a combination of this bandwidth with an aperture efficiency as high as possible, since this allows to minimize occupied space. The maximum aperture efficiency of the array achieved by CST MWS and in the measurements is 78 % and 86 %, respectively. This is considerably higher than what has been reported up to now in literature for wideband microstrip arrays.