This paper attempts to provide a panoramic picture of the research and development of substrate integrated circuits (SICs), presumably the next generation of high-frequency integrated circuits for GHz and THz electronics and photonics. This work begins with a summarized overview of current status of SICs-related research over microwave and millimeter-wave frequency ranges, and an outlook into their future development is then discussed with respect to the last unexplored (or rather limited) explored frontier of THz electromagnetic spectrum. With special interest in low-cost and matured CMOS and Si-related technologies, we would be able to examine the possibility of using SICs technologies within such matured processing platforms. This development may be enabled by the rapid deployment of through-silicon via (TSV) processes and related 3-D stack Silicon techniques as well as material research progress such as nanostructured and subwavelength plasmonics. In this way, SICs may allow us to anticipate and extrapolate their applications trends towards the THz frequency range where no tangible integrated circuits technology is available to date. Challenging issues and future directions are considered, pointing to a potentially cost-effective and performance-promising ICs solution for mass commercial applications.