Characterisation of a quasi-optical transmissometer for precise measurement of a sub-THz multenna

Analysis on estimating the input power of a non-linear multiplier, positioned at the focal point of a quasi-optical (QO) transmissometer driven by a vector network analyser (VNA), has been carried out. The multenna, or an integrated antenna with a multiplier, has the functionality of generating the second harmonic (300 GHz) of an antenna element resonating at 100 GHz. The output power from the mm-wave multiplier head, operating in the WR-10 waveguide band, was estimated using the QO transmissometer. The input power at 100 GHz to the multenna was critically measured using the R&S Spectrum Analyser and a WR-10 mixer. Additionally, the beam waist at the focal point of the QO transmissometer was estimated in the WR-10 waveguide band (75 - 110 GHz).