Nonuniform metasurface for wideband circularly polarized antenna using characteristic mode analysis

• Published in: International journal of electronics and communications 2023-12, Vol.172, p.154978, Article 154978
• Main Authors: Chen, Qiang, Yang, Jun, He, Changhui, Hong, Liang, Zhang, Di, Huang, Siyu, Yu, Fangli, Zhang, Lu, Xiong, Weihua, Zhang, Hou
• Format: Article
• Language: English
• Subjects: Characteristic Mode Analysis (CMA); Circularly polarized (CP); Low profile; Nouniform metasurface
• ISSN: 1434-8411; 1618-0399
• DOI: 10.1016/j.aeue.2023.154978

This paper proposes a nonuniform metasurface-based circularly polarized antenna utilizing characteristic mode analysis (CMA). The initial antenna is a corner-cut and slotted patch connected to the ground plane with a metal-via. By arranging 45° rotated slotted patches around it, CP radiation is achieved, forming a nonuniform metasurface. Through CMA, two satisfied CP modes are obtained by merging mode 1 and 4, as they exhibit similar far-field radiation patterns and surface current directions. Simulation results show that the proposed antenna has an S11 ranging from 4.1 to 5.7 GHz, a 3 dB AR bandwidth of 4.4–5.3 GHz, and an average 2 dB higher gain than the initial antenna with a maximum of 11.4dBic. The radiated mechanism is investigated to explain the bandwidth broadening caused by the arrangement of the 45° rotated slotted patches. It is found that the excitation of two orthogonal modes results in CP radiation and a wider bandwidth. Furthermore, a 2 × 2 array with sequential rotation is proposed to enhance the radiation properties. Simulated and measured results show that the antenna array achieves an S11 of 4–6.08 GHz, a 3 dB AR bandwidth ranging from 4.3 to 6.2 GHz, and a peak gain of 15.2 GHz, with a low profile of 0.08 λ0. A LHCP antenna can also be achieved through slight adjustment, making the proposed antenna suitable for military and civilian communication, and point-to-point links.