Wideband low‐profile endfire circularly polarized antenna using mode superposition technique.

In this article, a wideband low‐profile endfire circularly polarized (CP) antenna using magnetoelectric dipole is proposed. Designing a wideband electric dipole element is easy and well‐studied in the literature. However, designing a compact wideband magnetic dipole element is still a challenge. In this paper, the impedance bandwidth (IBW) of the magnetic dipole is enhanced by reducing the resonance frequency of higher‐order mode half‐TE310 with the help of rectangular slots placed at the null of mode half‐TE310. By combining the resonance frequency of mode half‐TE110 and mode half‐TE310, the magnetic dipole can yield a larger IBW (6.86–7.67 GHz, 11.14%) with smaller planar dimensions of 1.259λ0 × 0.363λ0 × 0.038λ0 (λ0 is the free space wavelength at the centre frequency). To generate a wideband endfire CP wave, a horizontally polarized electric dipole with a feed line is combined with the vertically polarized magnetic dipole. The measured IBW and axial ratio bandwidth (ARBW) are 11.65% and 12.02%, respectively, with a measured peak endfire gain of 5 dBic. The overall dimension of the proposed wideband low‐profile endfire CP antenna is 1.11λ0 × 0.66λ0 × 0.033λ0. [ABSTRACT FROM AUTHOR]