As the RF spectrum becomes increasingly crowded, demands on receiver flexibility and interference-tolerance are becoming more stringent. At the same time, while higher frequency bands are becoming available, they often exceed the upper frequency limits of state-of-the-art software defined receiver circuits and architectures. Thus, to make effective use of the entire available spectrum, receivers must be capable of mixing at these higher frequencies while remaining both resistant to interferers at other frequencies and instantly tunable across a wide frequency and bandwidth. In this dissertation we introduce a receiver architecture which is resistant to blockers, tunable across a wide frequency range, and capable of mixing up to 100 GHz. The development of such a solution comes across 3 generations of the HBT-based N-path receiver and this dissertation will cover each of these iterations as well as the underlying theory that establishes fundamental limits for its performance metrics. Finally, we will conclude with a summary that provides guidance for the further HBT-based N-path receiver designer.