Shared Aperture Dual-Band Dual Circularly Polarized Multibeam Antenna for Satellite-Assisted Internet of Vehicles

In many satellite communication systems, the uplink and downlink channels operate in different frequency bands and require orthogonal circular polarizations. In this article, a low-profile dual-band dual circularly polarized (CP) shared-aperture multibeam antenna is proposed for satellite-assisted Internet of Vehicles applications. The dual-band dual CP radiation is realized by a shared aperture array, which is composed of the truncated patch elements fed by microstrip line and the slot coupling patch elements fed by substrate integrated waveguide (SIW). To control the beam directions of the orthogonal CP radiation independently, two separated Rotman lens beamforming networks are suggested based on SIW coupling delay lines. A Ku-band prototype antenna is simulated, fabricated, and measured to verify the design. The measured common bandwidths of axial ratio (AR) and gain variation less than 3-dB for right-hand CP (RHCP) and left-hand CP (LHCP) are 11.4–11.9 GHz and 13.9–14.6 GHz, and with the peak realized gains of 21.3 and 21.9 dBic, respectively. At the center frequencies of 11.7 and 14.3 GHz in each band, the realized beam scanning ranges for RHCP and LHCP are ±35° and ±37°, respectively.