An electromagnetic coupler that couples antenna signals for a wideband antenna positioned between glass layers of an automotive windshield. The coupler includes a first co-planar waveguide (CPW) formed on one side of a glass layer and a second CPW formed on the other side of the glass layer, where the first and second CPWs are a mirror, or near-mirror, and 180° rotated images of each other. Both the first and second CPWs include a conductive plane where removed portions of the plane define a wide CPW section and a narrow CPW section that are electrically coupled to each other, and where the remaining portions of the conductive plane are ground planes, and where the electromagnetic signals are coupled through the glass layer between the wide CPW sections.