Universal tuner for on wafer load pull
View Patent ↗A universal load pull tuner for on wafer load pull and noise measurements is connected directly to the wafer-probe to minimize insertion loss and maximize the tuning range; it incorporates a suspended tuning module and an automated anti-tilting balancing mechanism with manual wafer tip planarization capability, all in a solid housing. The tuning module includes up to three mobile carriages and wideband tuning probes controlling independently impedances for up to three harmonic frequencies. The tuner is mountable under an angle matching the slope of the wafer probes and only requires a simple three axis positioner, without customized accessories, to operate.
1 . A load pull tuner for on-wafer measurements allowing a shortest connection to external wafer probes, a balanced and tilting-free operation, and a planarity adjustment of the external wafer probes, comprising: a housing (enclosure) containing a tuning module movable inside the housing, a balancing mechanism for the tuning module and a planarization mechanism for the external wafer probes performed by the tuning module, which is attached and directly RF connected to the external wafer probes;
wherein
the external wafer probes have a body, a coaxial connector protruding from the body at an angle and probe tips with a planarizing rotation axis;
and wherein
the tuning module has a test and an idle port linked through a slabline and both equipped with coaxial connectors and linked through a slabline, it and includes at least one mobile carriage remotely movable along the slabline and controlling a tuning probe insertable into the slabline and wherein the tuning module can be inclined on a vertical plane to match the angle of the coaxial connector of the external wafer probe and can be rotated around the planarization rotation axis of the probe tips;
and wherein
the balancing mechanism for the tuning module comprises at least one remotely controlled counterweight movable at controlled speed opposite to a movement of the center of gravity of the tuning module, which is caused by the movement of the at least one mobile carriage;
and wherein
the planarization mechanism of the external wafer probes comprises rotating the tuning module around the planarizing rotation axis of the probe tips of the external wafer probe of which the coaxial connector is directly connected to the coaxial connector of the test port of the tuning module.
2 . The load pull tuner of claim 1 being mounted on a wafer probe station using a three-axis (X-Y-Z) positioner; wherein the load pull tuner is mounted on the three-axis positioner at an angle on a vertical plane allowing alignment and direct connection of the coaxial connector of the test port of the tuning module with the coaxial connector of the external wafer microprobe.
3 . The balancing mechanism of the tuning module of the load pull tuner of claim 1 ,
wherein
the at least one counterweight with a mass M.CW is movable at a horizontal instantaneous speed V.CW whereby creating an angular dynamic momentum (M.CW*V.CW) which is equal and opposite to the vectorial sum of the angular dynamic momentums (Mi*Vi) of the mobile carriages (i=1, 2, . . . ) with associated mass Mi moving at associated instantaneous horizontal speed Vi.
4 . The balancing mechanism of tuning module of the load pull tuner of claim 2 ,
wherein
the tuning module comprises three (3) mobile carriages each having a mass M and movable at an instantaneous horizontal speed V,
and wherein
the counterweight has a mass of 3M and moves at opposite horizontal instantaneous speed adjustable between V, when all carriages move, V/2, when two carriages move, and V/3, when one carriage moves.
5 . The balancing mechanism of the tuning module of the load pull tuner of claim 3 ,
wherein
all carriages and the counterweight use an identical ramping up and ramping down time between instantaneous speed states.
6 . The planarization mechanism for wafer microprobes of the load pull tuner of claim 1 allowing the tuning module, of which the test port connector is directly attached to the connector of the external wafer microprobe, to be aligned with and rotated around the planarizing rotation axis of the probe tips.
7 . The planarization mechanism of the external wafer probes of claim 1 for controlling the rotation of the tuning module inside the tuner enclosure by an angle of at least ±5 degrees around the planarizing rotation axis of the probe tips comprising:
a set of adjustable gimble support devices between the tuning module and the tuner housing, a spring-loaded anchoring arrangement of the tuning module to the tuner housing, and a manually adjustable device controlling the angle.
8 . A device for attaching the body of the external wafer microprobe to the tuning module of the load pull tuner of claim 1 comprising an interface support block allowing the tuning module to rotate around the planarizing axis of the probe tips.
9 . The interface support block of claim 8 being attached to the body of the external wafer microprobe and to the tuning module.