Compact multi-carriage impedance tuner and method

A multi-carriage electro-mechanical impedance tuner, comprising

• a test port, an idle port and a circular parallel plate airline (slabline) between the ports,
• and at least two independent mobile carriages carrying disc-shaped conductive tuning probes;
• whereby the slabline comprises
• a) two parallel conductive discs, a top disc and a bottom disc, having a common center, similar diameter and being separated by a space (channel) between them,
• and
• b) a center conductor having toroid form and being centered in the space between the two discs and having the same center as the discs;
• whereby the discs and the center conductor form a circular transmission airline (slabline) with characteristic impedance Zo;
• and whereby the tuning probes slide in, out and along the channel;
• and whereby the carriages are radial arms, controlled by a first stepper motor, rotate around the center of the discs and slide on top of the top disc;
• and whereby a second stepper motor is mounted at the peripheral end of each radial arm and controls the tuning probe,
• whereby the axis of the second motor is perpendicular to the slabline discs;
• and whereby the tuning probe is rotating eccentrically around its own rotation axis, and, in a planetary fashion, around the center of the slabline discs, hereby sliding along the channel of the slabline and penetrating into the channel at adjustable depth, the depth being controlled by the second motor;
• and whereby the motors are driven by a tuner controller using electronic control boards, digital communication and software.