STC-20-08-S1 is an F-Band down-converter that converts millimeterwave signals from a frequency range of 90 to 140 GHz to the baseband at 10 MHz to 1.6 GHz. The down-converter requires 11.25 to 17.5 GHz at +3 dBm input power, which can be obtained from a standard 20 GHz synthesizer, such as Eravant models STL-SG-022203-S1 or SOT-02220313200-SF-B6. The down-converter has low harmonic levels and excellent gain flatness, making it a good candidate to extend low frequency test equipment for millimeterwave testing purposes.