This paper addresses the design and measurement results of two high frequency signal sources implemented in SiGe HBT technology. The 367 GHz signal source achieves a phase noise of -110 dBc/Hz at 10 MHz offset from the carrier and provides better than -8 dBm of output power. The 154 GHz signal source achieves a phase noise of -87 dBc/Hz at 1 MHz offset from the carrier and generates +7 dBm of differential output power. To the author's knowledge, the 154 GHz oscillator achieves the highest output power among silicon-based signal sources in this frequency range, and the 367 GHz signal source achieves the best phase noise among silicon-based signal sources in this frequency range. These results show the feasibility of implementation of high-performance sub-millimeter-wave circuits in advanced SiGe technology platforms.