Circularly polarized dual-band dipole antenna utilizing a transmissive type linear to circular polarization converter

In this article, we are proposing a linearly polarized (LP) printed dipole antenna (PDA) combined with a transmissive-type frequency selective surface (FSS). The proposed FSS converts LP waves to circularly polarized (CP) with two frequency bands with the corresponding center frequencies of f1 = 7.2 GHz and f2 = 9.1 GHz, respectively. The LP dual-band PDA is designed so that its impedance bandwidth (IBW) overlaps with the operating frequencies of the FSS converter. Based on the simulated and experimental results, the proposed PDA has two fractional IBW covering 6.98-7.29 GHz and 8.95-10.07 GHz. The average measured gains of the first and second frequency bands are about 6.23 dBi and 6.51 dBi, individually. Considering the advantages of linear-tocircular polarization conversion, the FSS polarization converter has been embedded on top of the antenna to achieve the desired circular polarization. Measured results show that the combination of the PDA and the FSS converter forms a CP which reveals a 3-dB axial ratio bandwidth (ARBW) in the first (6.91-7.42 GHz) and second (8.93-9.35 GHz) frequency bands.