A calibration technique for measurements of reflection from an open-ended waveguide

A simple calibration technique is presented for the measurement of the reflection coefficients of an open-ended waveguide. The accuracy of this calibration can be improved by using a waveguide isolator or attenuator between the adapter and the directional coupler. This calibration technique can be further improved by using the time domain gating feature of a vector network analyzer. The admittance of the open-ended waveguide has been measured using this calibration technique at X band and Ku band. The measured results show good agreement with the calculated ones and with those measured using waveguide calibration kits or TRL calibration kits. The calibration technique can be extended to other frequency bands provided that waveguide directional couplers and isolators at those frequency bands are available. The calibration technique can be used for measurements of dielectric permittivity and permeability using an open-ended waveguide system.