Recent advancements in differential Radio Frequency (RF) front-ends at millimeter-waves (mm-wave) create a need for high gain differentially fed arrays for 5G applications. In this paper, we present an ultra-wideband (UWB) mm-wave dual-polarized Tightly Coupled Dipole Array (TCDA) with a novel differential feeding network for operation across K-Wand 5G bands (viz. 22-80 GHz). Notably our novel H-Wall feed structure enables wide angle scanning. Full wave simulations show that the dual-polarized D-TCDA is capable of scanning to 60° at VSWR < 3 in both E and H planes. An UWB test board is presented for measurement of the array. Link budget analysis and measurements are presented for verification of 5G systems at mm-waves.