  In many cases beam coupling impedances or wake fields are calculated with
computer simulator such as CST Studio Suite, GdfidL Electromagnetic Field
Simulator and so on. But evaluation with the stretched-wire method is still
very useful by its flexibility to the change of the device-under-test
configuration, speed to get results and, more than anything, its accessibility
on the real devices. One of the drawbacks in the practical procedure,
difficulty of Thru-Reflect-Line calibration, is overcome using the calibration
method recently introduced in high frequency vector network analyzers, "2-X
THRU de-embedding". Here the procedure is explained in detail. The method has
been successfully applied to RF cavity and FX kicker measurement in the J-PARC
MR.
