Agilent / HP X914B Description:
This Sliding Load consists of a movable, tapered, low-reflection load element mounted in a section of precision waveguide.
A plunger controls the position of the load, and provides a controllable range of at least one half wavelength at the lowest waveguide frequency.
This movement permits the phase of the residual load reflection to be reversed so that this reflection can be separated from other small reflections in the waveguide system.
Sliding loads are often used in calibration procedures.