Determination of waveguide mode content using irradiance moments

We present a novel method for calculating the linearly polarized mode contents in an overmoded corrugated waveguide. The proposed method is based on calculating the low order irradiance moments of the measured radiated intensity profiles at several distances from the waveguide aperture. The method is validated by the data measured from a 63.5 mm diameter corrugated waveguide at 170 GHz and a 19 mm diameter corrugated waveguide at 250 GHz.