Ku/Ka Dual-Band Dual-Polarized Shared-Aperture Beam-Scanning Antenna Array With High Isolation

This paper describes the design and realization of a Ku/Ka dual-band shared-aperture beam-scanning antenna array based on the concept of structure reuse. The antenna consists of four Ku-band linear antenna arrays implemented by the substrate-integrated waveguide (SIW) and four Ka-band linear antenna arrays. To increase the aperture utilization efficiency, the Ku-band antenna is employed as some sidewalls of the Ka-band antenna. Thanks to this compact topology, the element spacing at two frequency bands is able to meet the requirement of a wide-angle beam scan. Both feeding networks of these two arrays are designed by proper SIW power dividers through the printed circuit board fabrication process. In addition, the self-filtering characteristic of the antenna, the orthogonal polarization, and the optimal layout of the array are employed to ensure the high channel isolation between the two antennas operating at different frequency bands over the whole beam scan range. The isolation between antennas is better than 28 and 70 dB at the Ku-band and Ka-band, respectively, scanning up to even 40°. The proposed shared-aperture concept and the design results have been validated by the experimental results.