A Duplex Dual Bands Circularly Polarized Patch Antenna for Satellite Internet

This paper proposes a duplex dual circularly polarized (CP) antenna for satellites communication. The downlink operates in 11.3 - 12.3 GHz with right-hand circular polarization (RHCP), and the uplink operates in 14 - 14.5 GHz with left-hand circular polarization (LHCP). The sequential rotation(SR) technique is used to achieve the circular polarization, and the CP axial ratio (AR) of operating bands are below 3 dB. The elevation angle of the 3-dB AR of the center frequency in uplink is larger than ±45°, and in downlink is larger than ±48°. This structure also uses an electromagnetic band gap (EBG) structure for decoupling and achieves an isolation more than -36.16 dB in the uplink. Finally, By calculating the beam direction patterns of 16 ×16 array with HFSS array factor calculation, the scan angle is larger than 23° when inputting 90° phase difference in phi=0° direction.