Wideband High‐Gain Low‐Profile Millimeter‐Wave Circularly Polarized End‐Fire Antenna Based on Magnetic Dipole Directors

ABSTRACT This letter proposes a wideband, high‐gain, low‐profile circularly polarized end‐fire antenna for 5G millimeter‐wave applications. The antenna consists of a substrate integrated waveguide (SIW) circularly polarized feeder, dual‐polarized directors, and coplanar waveguide (CPW)‐SIW transitions, with a low‐profile height of 0.14 λ 0 . The circularly polarized feeder exhibits wide bandwidth and reliable end‐fire radiation, while the dual‐polarized magnetic dipole directors enhance the end‐fire gain. Based on the feeder and magnetic dipole directors, a circularly polarized antenna is designed and fabricated. The −10 dB impedance bandwidth reaches 29.48%, with a peak gain of 11.14 dBic, demonstrating good impedance matching and high gain within the 5G millimeter‐wave band. Furthermore, the entire structure of the proposed antenna can be conveniently implemented using a single‐layer PCB substrate, achieving the desired low‐profile height.