Broadband probes for impedance tuners

A slab line impedance tuner system operable over a frequency bandwidth, the tuner system comprising:

• a slab line transmission including opposed slab conductor planes and a center conductor disposed between the slab conductor planes;
• a probe;
• a probe carriage carrying the probe;
• a carriage drive system for moving the probe carriage in a longitudinal direction parallel to the center conductor;
• a probe drive system for moving the probe in a transverse direction relative to the center conductor to position the probe closer to or further away from the center conductor;
• and
• wherein the probe includes:
• a plurality of probe sections, wherein each probe section has a different characteristic impedance from every other probe section at some position in the range of the longitudinal directional movement of the probe;
• and
• wherein a number of the probe sections forming the plurality of probe sections is sufficient to provide a desired characteristic impedance transformation for the frequency bandwidth, wherein the characteristic impedance of the tuner system is transformed probe-section by probe-section by the probe to intermediate impedance values to reach a target impedance value.

A probe for a slab line impedance tuner system operable over a frequency bandwidth, the tuner system including opposed slab conductor planes and a center conductor disposed between the slab conductor planes, a probe carriage and a drive system for moving the probe carriage in a longitudinal direction parallel to the center conductor, the probe comprising:

• a plurality of quarter wavelength, electrically conductive probe sections, each probe section having a nominal length dimension along the longitudinal direction of one quarter wavelength at a frequency at a midpoint of the bandwidth, and wherein each probe section has a cross-sectional profile defining a trough configured to straddle the center conductor as the probe is moved transversely toward the center conductor;
• wherein the probe sections are supported for movement together along the center conductor and in a direction transverse to the center conductor, the probe sections mounted together with no gaps between adjacent probe sections;
• and
• wherein a number of the probe sections forming the plurality of probe sections is sufficient to provide a desired characteristic impedance transformation for the frequency bandwidth, wherein the characteristic impedance of the tuner system is transformed probe-section-by-probe-section by the probe to intermediate impedance values to reach a target impedance value.