Simple extension of TRL calibration method of VANA

It is well known that in the broadband calibration of a vector automatic network analyser (VANA) using the through-reflect-line method, alternating valid and invalid calibrated frequency bands appear. The author describes an interpolation method for determining the reflection coefficient of a load, for which the reflection coefficient in frequency intervals is known. The interpolation method is based on the time domain filtering (gating) of the reflection coefficient. The interpolated reflection coefficient is then used with the through-match-reflect calibration method in the invalid frequency points