SIW patch array with internal coupling patches

A Substrate Integrated Waveguide (SIW) has been used to feed a progressive wave linear array of 16 double stacked patches. The amplitude and phase performance has been achieved by means of coupling patches, which are placed inside the SIW. An antenna prototype has been manufactured with a multilayer PCB structure. 16 dBi and 80 % peak gain and efficiency values at 17.7 GHz have been measured. A 10% reflection bandwidth (17 - 18.6 GHz) is achieved, although the usable bandwidth is reduced to 3% due to the typical array beam tilt dispersion of this kind of designs.