A Broadband Circularly Polarized Crossed Dipole Antenna for 5G Applications

ABSTRACT

This letter presents a cross‐dipole antenna designed for fifth generation (5G) applications, which achieves broadband circular polarization (CP) through the incorporation of parasitic strip elements. Its CP operating bandwidth meets the requirements of multiple 5G frequency bands. The antenna consists of an FR4 substrate, two metal layers printed on the substrate, a metallic reflector plate, and a coaxial feeder. The radiating structure comprises two dipole arms connected by split‐rings that provide phase delay, together with two sets of parasitic strips; this configuration yields three axial‐ratio nulls, thereby enabling a wide CP bandwidth. The antenna dimensions are 0.91λ ₀  × 0.91λ ₀  × 0.25λ ₀ (where λ ₀ denotes the free‐space wavelength at the center frequency). Prototyping and measurement validate that the antenna achieves a 64.6% fractional impedance bandwidth (IBW) (|S ₁₁ | < −10 dB, 2.82–5.51 GHz) and a 50.6% fractional axial‐ratio (AR) bandwidth (AR < 3 dB, 3.20–5.37 GHz). The overlapping bandwidth covers the 5 G_N77/N78/N79 bands. The measured average gain across the operating bandwidth is 6.7 dBi, with a peak gain of 7.8 dBi. The antenna features a simple and robust structure and a wide CP operating bandwidth for 5G applications, demonstrating potential for use in 5G wireless communications.