Ka-band aperture coupled microstrip antenna array fed by modified insulated image line

This paper presents a Ka-band aperture coupled microstrip antenna array fed by modified insulated image line. A Kapton layer of lower dielectric constant and the same width as the image line is used to insulate the image line from the ground plane. Conductor loss and attenuation in the guide are reduced. The measured E-plane and H-plane radiation patterns show very good results with higher gain, lower side lobe levels, and narrow beam width for the 2 mm thick Kapton layer. This structure has good potential for use at millimeter wave frequencies.