A 150GHz fundamental oscillator employing an inter-stage matching network based on a transmission line is presented in this letter. The proposed oscillator consists of a two-stage common-emitter amplifier loop, whose inter-stage connections are optimized to meet the oscillation condition. The oscillator is designed in a 130-nm SiGe BiCMOS process that offers f_T and f_MAX of 350GHz and 450GHz. According to simulation results, an output power of 3.17dBm is achieved at 147.6GHz with phase noise of -115dBc/Hz at 10MHz offset and figure-of-merit (FoM) of -180dBc/Hz.