In this thesis, vertical interconnect accesses (vias) are deployed as functional elements for the design of vertically integrated microwave components on multilayer low temperature cofired ceramic (LTCC) substrates. Functional via structures do not support transverse electromagnetic (TEM) modes but effectively behave like quasi-transmission lines up to 40 GHz if designed properly. Vertical integration is applied to a variety of passive microwave components including low- and band-pass filters, hybrid couplers, and N-way Wilkinson power dividers. The analysis for each component is comprised of the delineation of the design procedure, full-wave simulations, and lastly measurements up to 50 GHz of the manufactured prototype. The study is completed by examining the limiting case of via arrays, where many signal vias are in close proximity to each other, which gives insight into maximum coupling and crosstalk behavior.