A Decoupling Method for Closely Spaced Dual-Polarized Antennas Based on S-Parameter Consistency With Independent Control of Three Types of Coupling

In this paper, we introduce a novel and systematic approach, referred to as the S-parameter consistency method, to address the challenges of decoupling dual-polarized antennas with extremely small spacing. The method aims to achieve consistency in four pairs of S parameters to independently handle three types of coupling between antennas with two orthogonal polarizations. The primary advantage of this method lies in its capability to effectively decouple the antennas through simple configuration optimizations, eliminating the need for additional decoupling structures that would occupy additional space. This method is applied to decouple two ±45°-polarized patch antennas and a 1 × 4 array with an edge-to-edge distance of merely 0.023λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>c</i></sub>. We significantly enhance the worst isolation among any ports, raising it from > 8 dB to > 18 dB within this bandwidth of 3.3 – 3.6 GHz, whilst maintaining a compact antenna profile of only 0.086λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>c</i></sub>. Our approach presents a compact and efficient dual-polarized decoupling solution, particularly suited for applications where stringent space constraints are a primary concern.