A Parasitic Decoupling Structure for Dual-Polarized Patch Antenna Arrays

In this letter, a simple parasitic structure consisting of a microstrip L-section array and a microstrip U-section array is proposed for mutual coupling reduction of dual-polarization (DP) patch antenna array. The additional coupling paths are introduced by the structure in the cohorizontal polarization (CHP) and covertical polarization (CVP) directions of the array, respectively, to offset the original coupling signals. A 1 x 2 prototype array with the center to center distance of 0.42 lambda(0) is fabricated and measured for verification. The isolation between DP array with decoupling structure reaches to 37.5 and 33.6 dB on CHP and CVP at 4.3 GHz and envelope correlation coefficient is less than 0.004. The radiation gain of the antenna is almost not distorted while the total efficiency is increased from 84% to 91%. In comparison with other related works, our scheme has high isolation and high total efficiency with smaller space and lower profile.