A Simple Decoupling Network With Filtering Response for Patch Antenna Arrays

Facing the demand for decoupling and filtering for large-scale antenna arrays in modern communication systems, a transmission-line-based scheme is proposed and studied in this article. Different from other decoupling networks published recently featuring narrow decoupling bandwidths and high spurious levels, the proposed approach uses simple T-shaped networks where decoupling and filtering responses are realized simultaneously, leading to high-frequency selectivity and improved decoupling bandwidth. The proposed design is a simple 1-D configuration but powerful for 2-D arrays. Based on the study case of a $4\times {4}$ dual-polarized patch array, theoretical analysis and full-wave simulation are carried out to verify the performance in decoupling and frequency selectivity of this method. A prototype is further fabricated, assembled, and measured to demonstrate the performance of the proposed method in practice. The measured and simulated results are consistent with each other where a low insertion loss of around 0.6 dB is observed. The results denote that the proposed method is easily realized with a very small effect on the radiation performance of antenna elements, making it to be a potential and valuable decoupling and filtering solution for large-scale arrays.