Wideband circularly polarized magnetoelectric dipole antenna with I-slot for C-band applications

Abstract

This paper presents a circularly polarized wideband magnetoelectric dipole antenna with a defective semicircular patch for C-band applications (4–8 GHz). In the proposed design, in order to get proper impedance matching and stable gain, a pair of folded vertical patches is shorted between a pair of defective semicircular patches and minimum ground plane. The defective semicircular patches work as an electric dipole, while the vertical patches work as a magnetic dipole. The Γ-shaped single-feed structure is used to excite both dipoles together to achieve symmetrical radiation patterns. Minimum ground and the folded structure maintain the low profile of the presented design. The circular polarization is obtained by incorporating I-shaped slots in semicircular patches, extending to the lower and upper sides of the curved edges symmetrically on the both sides. A prototype was manufactured and the measured results agreed well with the simulated results. The results show an impedance bandwidth of 60.37% (S11 < − 10 dB) from 3.71 to 6.91 GHz, 3-dB axial ratio bandwidth of 20.60% from 3.71 to 4.55 GHz and a broadside stable gain of 6 ± 0.5 dBic. The antenna also shows good radiation efficiency of around 80% over the entire operating range. Therefore, the proposed antenna can be used in 5G Wi-Fi (5.15–5.875 GHz) wireless communication systems and several C-band applications.