Tri-Band Aperture-Shared Antenna Array Using Scalable FSS-Based Electromagnetic Transparent Structure

In a tri-band aperture-shared array (TBA), the low-band (LB) dipole often deteriorates the radiation patterns of the middle-band (MB) and high-band (HB) antennas due to shielding effects. To address this issue, a novel dual-band electromagnetic transparent structure (DBTS) is firstly proposed and used to realize a TBA. The DBTS achieves two tunable electromagnetic transparent frequency bands by periodically loading capacitive patches and meander lines to an inductive strip. Meanwhile, the DBTS features flexible frequency band scalability by loading additional serial L-C tanks. Then the DBTS is utilized to construct the LB dipole of a TBA, with its electromagnetic transparent bands allocated at MB and HB simultaneously. The proposed array realizes an aperture-shared operation within the frequency ranges covering 0.65-0.88 GHz (LB), 1.92-2.18 GHz (MB) and 3.3-3.8 GHz (HB). The LB dipole induces minimal shielding to the MB and HB antennas, resulting in their restored radiation performance with broadside gain deviation of less than 0.6 dB.