Broadband, Low Profile, Circularly Polarized, Slot Antenna With S‐Shaped Coupling Structure for Vehicle‐to‐Satellite Communications

ABSTRACT In this study, a low‐profile circularly polarized (CP) slot antenna featuring an S‐shaped coupling structure is proposed for vehicle‐to‐satellite communications. By leveraging the S‐shaped coupling feed, both wide impedance bandwidth and CP radiation are achieved. In addition, a defected ground structure (DGS) is incorporated to broaden the axial ratio (AR) bandwidth. The proposed antenna covers a −10 dB impedance bandwidth of 89.7% (6.7–17.6 GHz) and a 3‐dB AR bandwidth of 70.7% (7.4–15.5 GHz). It exhibits right‐hand circular polarization (RHCP) at broadside, with a maximum gain of 3.9 dBic. Given its compact profile and broadband performance, this antenna is a promising candidate for X/Ku‐band vehicle‐to‐satellite communication systems.