This paper proposes a new design of a triple-band dual-polarized indoor base station antenna for mobile communication systems serving the 2G, 3G, 4G, and the new sub-6 GHz 5G applications. The design consists of two orthogonal dipole antennas to provide dual polarization. Each dipole consists of three different radiator types - elliptical dipole, bowtie dipole, and cat-ear shaped arms for different bands. The proposed antenna offers three broad bands with the fractional bandwidths of 31.3% (0.7-0.96 GHz), 55.3% (1.7-3 GHz), and 14% (3.3-3.8 GHz) which can be controlled independently. The design also offers stable radiation patterns within the desired frequency bands, high polarization purity and, a simple feeding structure with a compact size and low profile which make this new design an ideal candidate for indoor mobile base stations serving the 2G, 3G, 4G, and the new sub-6GHz 5G applications.