High-Efficiency Dual-Polarized Array Antenna Using Low-Loss Transmission Line at <i>Ka</i> Band

A <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i>-band high-efficiency 8 × 8 dual-polarized patch array antenna is presented. With air as the primary transmission medium, the double-sided even-mode air-suspended line has a low attenuation constant, thereby realizing low-loss transmission. A 2 × 4 subarray fed by this low-loss line through coupling slots is proposed at 35 GHz. By extending the subarray, an 8 × 8 dual-polarized array is finally designed. Two independent feeding networks composed of this low-loss transmission line are skillfully designed to excite two orthogonal linear polarizations. The experimental results indicate that the realized maximal gains and the corresponding radiation efficiencies are 22.54 dBi and 74.53% for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i>-polarization, 23.35 dBi and 87.1% for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i>-polarization.