Triband Dual-Polarized Dipole Antenna With Controllable Bandwidths for 5G/LTE Applications

A low-profile triband dual-polarized dipole antenna with stable radiation pattern and gain, as well as controllable bandwidths for base-station applications is proposed. Two crossed dipoles, which are fed by microstrip-to-slot line baluns, are used to generate stable radiation for +/- 45 degrees-polarization at a very broad frequency band of 2.3-5.5 GHz, while an octagonal ring and triangular stubs are utilized to introduce two notched bands ataround 2.8 and 4.2 GHz, respectively, which divide the wide band into triple bands. It is beneficial that the triple bandwidths in this design can be controlled by tuning the location and total length of the parasitic ring and stubs. The proposed antenna achieves triple operating bands at 2.25-2.72 GHz, 3.24-4 GHz, and 4.57-5.16 GHz. Stable half-power beam width of 65.2 degrees +/- 4.3 degrees at the lower band,72.2 degrees +/- 6.4 degrees at center band, and 66.5 degrees +/- 3.8 degrees at the higher band are obtained. Additionally, the gains of the three bands are stabilized in small ranges of 8.5 +/- 0.5 dB, 8.4 +/- 0.4 dB, and 8.2 +/- 0.6 dB, respectively. These excellent performances make our design beneficial for practical applications.