Design of a Dual-band Shared-aperture Radar Array Using Printed Dual-loop Antennas

In this paper, we propose a shared-aperture S/X dual-band radar array using printed dual-loop antennas. The proposed array consists of one S-band element and nine X-band elements, where the coupled-fed dual-loop structure is applied for broadband matching characteristics. The proposed X and S array elements are then stacked to share a limited size aperture. Thicknesses of all layers including the air gap are optimized so that the S-band element has electromagnetic (EM) transparent characteristics in the X-band. To verify the feasibility of the proposed array, the reflection coefficient and bore-sight gain are investigated in the S/X-band.