Comparison of two intrinsic efficiency calibration method for low loss waveguide section

Two methods based on one-port measurements are introduced for intrinsic efficiency calibration of low loss waveguide section. One of the methods are similar to the multiline one-port (ML1P) technique, which are proposed by Wiatr. While, we change the ML1P method slightly by using a flush short and a 1/4λoffset short. The other method takes advantage of the developed function of PNA-X. After statements of calibration procedures for a U band waveguide section, calibration results are compared with the theory calculation value.