Single-dipole antenna on a metasurface for broadband circularly polarized radiation

Abstract

This paper investigates a low-profile broadband circularly polarized (CP) antenna, which is composed of a single-dipole on a metasurface. Surface waves propagating on the metasurface are excited to generate extra-resonances for the antenna system, which are utilized to broaden the antenna bandwidth. The metasurface, which is a lattice of 5 × 5 truncated-corner square patches, is used for converting the linearly polarized wave from the dipole source to CP wave at the broadside. A prototype operating at the frequency of about 2.4 GHz is designed, fabricated, and tested. For an easy realization and a low-cost, the dipole and metasurface are printed on top and bottom sides of a single substrate, respectively, which is placed above the ground plane via a structural-foam. The final design, with an overall size of 100 mm × 100 mm × 14.2 mm (0.8λ_o × 0.8λ_o × 0.114λ_o at 2.4 GHz), resulted in a |S₁₁| < –10 dB bandwidth of 2.0–2.72 GHz (27.6%) and a 3-dB axial ratio bandwidth of 2.3–2.8 GHz (19.6%). In addition, the antenna yielded a broadside right-hand CP radiation with a peak gain of 8.67 dBic and radiation efficiency of >93% within the operational bandwidth.

Keywords:

• Single-dipole
• metasurface
• surface wave
• broadband
• linear polarization
• circular polarization
• polarization conversion