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In this article, a novel wideband circularly polarized (CP) square‐slot antenna with perturbation elements is proposed. The antenna comprises of an inverted L‐shaped feeding line, pairs of corner cuts, a rectangular slot, and a semi‐elliptical patch. The numerous CP resonant modes were excited simultaneously using these slots and patches as perturbation elements. To verify this concept, an antenna prototype was built and tested. The measured results indicate the −10‐dB impedance bandwidth (IBW) is 69.2% (2.42–4.98, 3.7 GHz) and 3‐dB axial ratio bandwidth (ARBW) is 59% (2.58–4.74, 3.66 GHz). Furthermore, the measured peak gain is 4.3 dBi, and the gain variation within the certain bandwidth is less than 1 dB. Therefore, the presented antenna features wide CPBW and stable gain characteristics. [ABSTRACT FROM AUTHOR]

In this paper, a novel 2 × 2 square slot wideband circularly polarized antenna array (CPAA) is proposed. The antenna consists of a sequential rotation feeding structure, four asymmetric U‐shaped feeding strips and a slotted ground plane formed by four square slots with cut corners, four rectangular slots, and four L‐shaped strips. In contrast to the traditional L‐shaped feeding strips used in CPAAs, an asymmetric U‐shaped feeding strip is, for the first time, presented to improve the antenna performance. By using these strips and slots as perturbation elements, the slotted CPAA is able to stimulate multiple circular polarized (CP) radiation modes, resulting in wideband CP radiation. The measured results revealed that the 3‐dB axial‐ratio (AR) bandwidth for AR < 3 reached 81.3% (1.75–4.15 GHz), whereas the −10‐dB impedance bandwidth (|S11| < −10 dB) reached 88.6% (1.96–5.08 GHz). [ABSTRACT FROM AUTHOR]