STE-KF1803-S1 is a WR-03 x18 frequency extender that uses an input signal from 12.22 to 18.33 GHz at +3 dBm to produce a 220 to 330 GHz RF signal at -12 dBm. The extender is designed and manufactured as a bench top unit to extend the low frequency synthesizer or sweeper, such as Eravant models STL-SG-022203-S1 or SOT-02220313200-SF-B6, without losing functionalities and features. The extender also features adjustable legs, which can be removed, to allow for an easy test set up.