A design of K/Ka dual-band shared-aperture array antenna with high isolation

This paper describes the design and realization of a dual-band shared-aperture antenna array based on the concept of structure reuse. The antenna consists of a 4×2 K-band dipole array and a 4×4 Ka-band waveguide array constructed by the 4×2 K-band antenna structure and supporting plates. Both feeding networks of these two arrays are integrated together through the printed circuit boards (PCB) fabrication process. To increase the aperture efficiency, the K-band antenna is employed as the wall of the Ka-band radiating waveguide. Thanks to this topology, different antennas have high isolation with low mutual coupling between them. The isolation between two ports is better than 38 dB and 90 dB in Ka-band and K-band respectively. The experimental results have verified the proposed scheme and the design process.