High‐Order Characteristic Modes Suppression for Cross‐Band Decoupling in Shared‐Aperture Antenna Array

• Published in: Chinese Journal of Electronics 2022-11, Vol.31 (6), p.1121-1128
• Main Authors: LU, Xiaochi, CHEN, Yikai, SHEN, Tongsheng, GUO, Shaojun, ZOU, Chunrong, YANG, Shiwen
• Format: Article
• Language: English
• Subjects: Base station antenna; Characteristic modes (CMs); High‐order modes suppression; Shared‐aperture antenna
• ISSN: 1022-4653; 2075-5597
• DOI: 10.1049/cje.2022.00.188

In dual‐band shared‐aperture base station antennas, the secondary radiation (SR) field caused by cross‐band couplings always leads to radiation pattern distortion. In this work, the SR field caused by the coupling is attributed to the excitation of the target high‐order modes from the perspective of the characteristic mode. To effectively suppress the target modes, L‐shaped slots are proposed to load the arms of the radiator and altering the current paths. As compared with conventional dipoles without L‐shaped slots, the proposed antenna generates less SR field. Therefore, the radiation pattern of the high‐band antennas keeps stable in a dual‐band shared‐aperture antenna array environment. Prototype of a dual‐band antenna array consisting of the proposed low‐band (LB) antenna and a 4 × 4 high‐band (HB) antenna array is fabricated. Simulated and measured results show that the designed dual‐band array operates at both 0.74–0.82 GHz and 3.30–3.80 GHz. The experimental results verify that the cross‐band decoupling has been achieved with the high‐order mode suppression.