Wideband and Low-Profile Differential-Fed Circular Polarized Antenna

This paper proposes a wideband, differential-fed circularly polarized (CP) antenna designed for millimeter-wave (mmw) applications. The antenna demonstrates advantages in terms of profile, gain, and bandwidth. In the design approach, an I-shaped differential-fed slot is introduced, and complementary dipoles are added in the same plane to contribute to CP radiation. As a demonstration, a circularly polarized antenna operating at 65 GHz is designed. Simulation results indicate an overlapping bandwidth of 12.3% (62.84-71.22 GHz) for impedance matching, axial ratio, and gain. The antenna achieves a flat in-band gain with a peak gain of 10.77 dBic. The realization of a wideband and low-profile CP antenna is of great practical significance to meet the demands of mmw communication systems for high-capacity, high-rate data transmission and easy integration.