A Dual-Polarized Filtering Base-Station Antenna with Compact Size for 5G Applications

A compact dual-polarized filtering base-station antenna is presented in this letter. The entire size (include the ground plane) of the element is only 0.53λ × 0.72λ × 0.14λ (λ is the wavelength of the central working frequency). Four vertical slots etched on the coupling cross slot are for improving the high-frequency suppression of the antenna. The C-slots on the Gnd1 reduce the cross-polarization ratio at the axial direction. The antenna shows a wide working bandwidth of 25.6% and a low cross-polarization ratio about 22 dB. In order to validate the design, a 1 × 3 linear array is fabricated and tested. The antenna array works at 3.3–4.0 GHz with the average gain about 11 dBi. Besides, the array remains a good out of band rejection more than −20 dB up to 9 GHz which exhibits a good harmonic suppression performance over a wideband.