The Farran Technology Ltd (FTL) FEV-XX frequency extension modules are test equipment to extend the frequency range of customer owned Vector Network Analyzers. Together with the FTL frequency extension controller FEC-01/FEC-02 they allow measurements in the range 50 GHz to 110 GHz (W - band) using Agilent PNA/PNA-X or Anritsu 37XXXD/Vector Star VNAs with ongoing development of 110 – 170 GHz system.