An X-/Ka-Band Shared-Aperture Phased Array Antenna by Structure Reuse Strategy of Embedded Dielectric Resonator

This article proposes a new topology for an X-/Ka-band shared-aperture phased array to achieve high aperture utilization. The unit cell of the shared-aperture array consists of one X-band element and 3 × 3 Ka-band elements. The Ka-band element is an embedded rectangular dielectric resonator antenna (DRA) with a metasurface etched on its top side. To realize left-handed circular polarization (LHCP), a cross-slot and a couple of arc-shaped slots are employed in the coupling feed mechanism. The X-band element is a dual-feed magnetoelectric dipole antenna (MEDA) with dual CP capabilities. By hollowing out the center and the sides of the dipole antenna, 3×3 Ka-band elements can effectively share the same aperture with the X-band element. The idea of a structure reuse strategy allows for independent frequency and radiation control for the proposed shared-aperture structure. A shared-aperture array prototype, comprising 3 × 3 X-band and 10 × 10 Ka-band elements, was fabricated and measured for performance verification. The measured results show that the proposed array can achieve an impedance bandwidth (active VSWR ≤ 2:8) from 7 to 8.5 GHz for the X-band and from 26 to 28 GHz for the Ka-band. In addition, it can realize ±45° beam scanning with an axial ratio (AR) variation of less than 5 dB for both bands.