Rectangular-waveguide vector-network-analyzer calibrations with imperfect test ports

We present a strategy for correcting for imperfect interfaces between the test ports of a vector network analyzer, the calibration standards and the devices under test. This corrects for the inconsistencies in calibrations introduced by use of flush thrus and flat shorts as calibration standards. The approach is based on equivalent standard definitions that are easy to implement in conventional network analyzers. We present analytic formulas for these definitions and demonstrate them in WR-90 rectangular waveguide.