28/38 GHz Dual-band Dual-polarized Highly Isolated Antenna for 5G Phased Array Applications

This paper proposed a new dual-band dual-polarized array antenna operating at 28 GHz and 38 GHz for 5G communication applications. Three stacked patches are adopted to achieve the dual-band operation. The lower band from 27.48 to 28.50 GHz is achieved by using the lower large patch, which is couple-fed by the middle patch. While the upper band from 36.94 to 40.43 GHz is achieved by using the middle and upper patches. The two patches resonant at 38 and 40 GHz respectively and the two resonant modes coupled together, which greatly enhances the upper band. To increase the polarization isolation in the lower band, a shorting pin connecting the lower patch and ground is utilized. Taking advantages of the multi-layer technology, the position of the vertical feeding probe between the middle patch and lower patch is slightly shifted to ensure the good impedance matching in both lower band and upper band. For the antenna element, the simulated -12 dB bandwidths are 27.48-28.50 GHz and 36.94-40.43 GHz for the two bands, respectively. The in-band gains are over 6 dBi in the lower band, and over 4 dBi in the upper band. For the 2×2 antenna array, the isolations are better than 20 dB in both bands.