Design of Compact and High Isolation Dual-Polarized Antenna Array via Plasmonic Meta-Structure

We propose a compact and high isolation dual-polarized antenna array based on plasmonic meta-structure operating at 2.58 GHz. The compact principle of the dual-polarized antenna is mainly based on spoof surface plasmon polariton (SSPP) radiation patch to support SSPP modes, which is fed by spatially coupled excitation. Due to the slow-wave feature of SSPPs, the size of dual-polarized radiation patch is reduced to
$0.2\lambda _{0}\times 0.2\lambda _{0}$
, and the total antenna size is reduced to
$0.39\lambda _{0}\times 0.39\lambda _{0}$
, which is much smaller than that of the traditional microstrip antenna with
$0.5\lambda _{0}\times 0.5\lambda _{0}$
. The cross-polarization coupling between two polarization ports can be improved to below −32 dB, showing high isolation characteristics. Besides, a
$3\times 3$
compact antenna array is also designed, fabricated, and measured to verify the feasibility of its extension to larger-scale antenna systems. Both simulated and measured results of the proposed compact antenna and the antenna array illustrate compact profiles, good ±45° radiation performance, and high isolation levels, which have potential application values for the massive multiple-input and multiple-output (MIMO) base stations.