In this paper, a low profile ultra-wideband microstrip antenna is proposed for millimeter wave applications below 100 GHz to meet the demands of high data rates in the future wireless communication systems. The proposed antenna consists of a non-uniform hexagon shape radiating element on the top of 13th layer of ceramic. The proposed antenna geometry is designed using Low Temperature Co-fired Ceramic (LTCC) technology for 3D multilayer vertical integration. HFSS and CST Studio are used for design and simulation of this ultra-wideband antenna. This antenna covers a bandwidth of 33.5 GHz that ranges from 62.5 GHz to more than 96 GHz with a peak gain of 5.7 dBi, stable radiation pattern across the bandwidth, and compact size of 3.16  3.2 mm 2. The limitation of the narrow band in microstrip antenna is successfully dispensed by increasing the matching impedance bandwidth to more than 40 %. The proposed microstrip antenna is very useful for modern wireless communication systems because of its capability of covering a very wide bandwidth with favorable impedance matching and a stable radiation pattern at the considered frequency range. This antenna has another advantage in terms of the ability to be directly integrated with other RF chips using LTCC multilayer technology.