In this talk I will discuss three research projects that leverage several areas of circuits, systems and device physics to solve new problems in radio frequency applications. The first part of my talk begins in circuits with the millimeter scale and discusses our research aimed at significantly increase the speed, power output and efficiency of mm-wave power amplifiers (PA). Current state-of-the-art Si PAs above 20 GHz suffer from low power-added-efficiency (PAE) and output power, typically < 20% and < 0.5W. I will present our recent results in the development of high PAE (20% - 50%) PAs above 45 GHz using SiGe and 45 nm CMOS and also our work on the development of novel power combiners. The second part of my talk will present a non-line-of-sight position location system using low frequency magnetoquasistatic fields (&#955;~1 km). Our initial application is in tracking an American football during a game, which is extremely difficult due to the constant obstruction of the ball by the players. We circumvent this problem by using magnetoquasistatic fields, which are not perturbed by the presence of human bodies, to develop a novel tracking system. I will present our recent research results in collaboration with Disney/ESPN that show the ability to track a football across a football field with approximately 1 ft average error. In the final part of my talk I will discuss our work using nanoscale spin-torque oscillators for RF signal generation.