Millimeterwave tuners with external airline
View Patent ↗A passive slide screw load pull tuner structure can be used on-wafer, in millimeter-wave frequencies from 20 to 110 GHz. It uses a short external (not extended) slabline, mounted sloped and allowing direct contact with the wafer probe, thus permitting the tuning probe to come as close to the wafer probe as physically possible; this minimizes the insertion loss between tuner and DUT and, thus, generates the maximum possible tuning range of a passive electro-mechanical impedance tuner.
1. A slide screw impedance tuner having a test port and an idle port, said tuner comprising
a) a tuner body,
b) at least one horizontally sliding carriage comprising a precision vertical axis,
c) a parallel plate airline (slabline) having a center conductor, a test and an idle port, in which said slabline metallic tuning probe(s) are insertable and
d) carriage and vertical axis remote control using stepper motors, gear, electronic interface and control firmware,
whereby the slabline is externally mounted and anchored sloped to the tuner body to match the angle of an auxiliary connected wafer probe,
and whereby the tuning probe(s) are mounted on bracket(s) having a horizontal section and a sloped section, which transpose the original horizontal-vertical movement of the carriage and vertical axis to a movement of the tuning probe, parallel and perpendicular to the center conductor of the sloped slabline.
2. The tuner of claim 1 , whereby the test port of the slabline is the test port of the tuner and is connected directly to the wafer probe.
3. The tuner of claim 2 , whereby the idle port of the slabline is connected to the idle port of the tuner, using a low loss transmission line.
4. The tuner of claim 3 , whereby the transmission line is a RF cable.
5. A movement control algorithm for tuning probe of the tuner as in claim 1 ,
whereby
a) moving the probe towards the test port requires moving first the carriage towards the test port and then moving the vertical axis towards the center conductor, and
b) moving the probe away from the test port requires first moving the vertical axis away from the center conductor and then moving the carriage away from the test port, and
c) moving the probe towards or away from the center conductor requires moving the vertical axis first towards or away from the center conductor accordingly and then moving the carriage towards or away from the test port,
d) moving the probe parallel and perpendicular to the center conductor requires moving parallel first then perpendicular.
6. A coordinate system for tuning probes of tuner as in claim 1 ,
whereby
the coordinate system comprises axes A parallel to the center conductor, and B perpendicular to the center conductor,
and whereby
the tuner carriage moves horizontally in X and the vertical axis in Y,
and whereby
increasing A and X moves the probe towards the test port and increasing B and Y moves the probe towards the center conductor,
and whereby
for a A movement parallel to the center conductor and a B movement perpendicular to the center conductor, new horizontal coordinates Xa and Xb and vertical coordinates Ya and Yb are
Xa =(INT)( A *cos(Φ)), Ya =(INT)( A *sin(Φ)) and
Xb =(INT)( B *sin(Φ)), Yb =(INT)( B *cos(Φ)),
whereby
Φ is the angle between the horizontal level and the center conductor of the slabline.