Low-Profile Aperture-Shared X/Ka-band Dual-Polarized Antenna for DBF-SAR Applications

Kurzfassung

In this paper, a novel low profile aperture-shared X/Ka-band dual-polarized antenna array is proposed for space-borne digital beamforming (DBF) synthetic aperture radar (SAR) applications. To begin with, the DBF concept and its operation mechanism for SAR system are discussed. In this work, every 2 × 2 Ka-band elements are combined as a subarray and connected to a channel while each one X-band element is connected to a channel. Then, a novel slot-antenna based on substrate-integrated-cavity (SIC) is proposed. The resonant frequency can be controlled by adjusting the length of the U-shaped slot. To share a same aperture, the X-band antenna is interlaced with the Ka-band subarray on the same plane. To verify the concept, an antenna operating at 9.6/35.75 GHz is designed, prototyped and tested. The results demonstrate good performance in terms of impedance matching, channel isolation, and cross polarization level. Such highly integrated low profile antenna can significantly reduce the potential cost of the DBF-SAR system.