Impedance tuners used in high power measurements suffer fast heating and consequently thermal expansion of the central conductor, which has a very small mass and is thermally isolated from the tuner housing. This leads to false measurements or catastrophic tuner failure (short) of either the DUT or the tuner. A method is introduced for cooling the centre conductor down to tolerable limits by using forced air conduits inside the slabline channel. Alternatively and/or additionally, alternative centre conductor material to traditional stainless steel rod is used (INVAR) which minimizes the thermal expansion of the centre conductor by a factor of at least 10. Practical tests have shown significant thermal behaviour improvement.
High Power Tuners and Method / 15/136,511
Saturday, April 16, 2016