Planarity control for load pull tuner on wafer
View Patent ↗Planarity adjustment of RF microprobes in a load pull setup on wafer, using a low-profile impedance tuner that is mounted on a 3-axis tuner positioner under an angle matching the angle of the wafer probe. is performed using a swivel or a gimbal connecting the vertical axis of the 3-axis tuner positioner with the tuner body. A swivel is used when there is a single geometrical axis between the RF microprobe tips and the tuner slabline. If the axis of the slabline is not aligned with the tips of the RF microprobes, then a gimbal is used to connect the tuner body with the vertical axis of the 3-axis tuner positioner. In all cases the assembly rotates around the axis of the probe tips and allows fine adjustment of the planarity.
1 . A planarity control mechanism for RF wafer microprobes attached to load pull tuners comprising:
an interface block inserted between the tuners and the RF wafer microprobes, and a rotational link between the tuner and a vertical axis of a three-axis positioner, and means for controlling a rotation of the tuners and the attached RF wafer microprobes,
wherein the RF wafer microprobes have a body, probe tips and a coaxial connector; the tuners have a slabline with a center conductor linking a test and an idle port which are equipped with coaxial connectors,
and wherein the interface block allows the coaxial connector of the RF wafer microprobe and the coaxial connector of the tuner test port to be aligned, matched, and directly connected,
and wherein the tips of the RF wafer microprobes, the coaxial connector of the test port and the center conductor of the slabline share a rotation axis;
and wherein the rotational link comprises a body attached to the vertical axis and a swivel linking the body with the tuner and allowing the tuner to rotate with the microprobe around the shared rotation axis between the tips of the RF wafer microprobes and the center conductor of the slabline,
and wherein the means for controlling the rotation of the tuners comprise:
a control stub aligned with the center conductor rotating inside the body of the rotational link, and a control wheel.
2 . The planarity control mechanism for RF wafer microprobes of claim 1 ,
wherein the rotational link between the tuner and the vertical axis of the three-axis positioner has a sloped extension holding the swivel with a nominal slope allowing the alignment and direct connection of the coaxial connector of the tuner test port to the coaxial connector of the wafer probe.