Sliding Matched Terminations

The waveguide sliding matching termination is a type of precision calibration component for vector network analyzers, which is mainly composed of air lines and cylindrical ferrite inside.

The characteristic impedance of an air line is determined by the diameter of the inner conductor and the inner diameter of the outer conductor. A regular termination has its inner conductor connected to a material with a resistive coating, and there are correction holes in the middle of the coating to optimize the impedance value of the termination matching. The air line of sliding termination makes its characteristic impedance more accurate than that of ordinary termination.

Ferrite magnetic rods can absorb most of the magnetic field energy. When we slide the ferrite magnet during the calibration process, the offset length, reflection coefficient, and phase of the air line all change.

By sliding the ferrite magnetic rod, impedance and return loss can be optimized to ensure calibration accuracy in the high frequency range. By moving the position of the termination to change the reflection phase of the termination reflection coefficient, it can distinguish the testing error of the termination in the system or measurement, and is widely used for precision calibration of vector network analyzers. Due to its precise adjustment ability of characteristic impedance, sliding terminations perform well in high-frequency applications.