Load pull tuner on waveguide wafer-probe
View Patent ↗A computer-controlled load pull tuner is embedded in a quarter-circle waveguide-to-wafer-probe adapter and creates a compact and handy assembly. The tuner includes two, along the 90-degree arc of the waveguide, sliding carriages, each holding a tuning probe inserted at fixed penetration without cumbersome vertical axis mechanisms. The carriages holding the tuning probes are spring preloaded against the waveguide wall and can tilt, when hitting a stop, lifting the tuning probes out of the waveguide cavity, thus allowing for a low residual reflection and high transmission behavior. On top of full load pull capacity, the assembly can be used for instantaneous s-parameter measurement when the tuning probes are lifted. High-speed calibration and tuning algorithms allow efficient operation.
1. A load pull tuner-waveguide-to-wafer-probe adapter assembly comprising:
a partly slotted quarter-circle waveguide-to-wafer-probe adapter, and two remotely controlled reflective tuning probes, a first tuning probe and a second tuning probe,
wherein
the partly slotted waveguide-to-wafer-probe adapter comprises:
a rectangular waveguide transmission line having a top and a bottom broad wall and two narrow side walls, forming a 90-degree waveguide arc and being connected on one end to a waveguide flange and on the other end to a wafer-probe head;
and wherein
the 90-degree waveguide arc includes two slots, centered on the top broad wall along the waveguide, a first slot towards the wafer-probe head and a second slot towards the waveguide flange, each said slot being at least one half of a wavelength long at a minimum frequency of operation of the load pull tuner;
and wherein
two mobile carriages, a first mobile carriage and a second mobile carriage slide along the top broad wall of the waveguide arc, moved by a radial arm, which rotates around a virtual center of the waveguide arc and is controlled using stepper motors and appropriate gear;
and wherein
the first tuning probe is attached to the first mobile carriage and the second tuning probe is attached to the second mobile carriage, each said tuning probe being inserted contactless at fixed penetration into the associated slots,
and wherein
the mobile carriages are spring-loaded towards the broad wall of the waveguide arc and can tilt away from the waveguide broad wall, when hitting a stop, and lift the tuning probes out of the waveguide slots.
2. The load pull tuner-waveguide-to-wafer-probe adapter assembly of claim 1 ,
wherein
the tuning probes are, at least partly, metallized rods.
3. The load pull tuner-waveguide-to-wafer-probe adapter assembly of claim 1 ,
wherein
the tuning probes are, at least partly, metallized dielectric pellets.
4. The load pull tuner-waveguide-to-wafer-probe adapter assembly of claim 1 ,
wherein
the tuning probes are initialized to withdrawal positions by moving the carriages beyond the stops, causing them to tilt away from the top waveguide broad wall, lifting the tuning probes out of the waveguide slots and defining associated initialization (withdrawal) positions X 1 =0 and X 2 =0;
and wherein
the first carriage moves the first tuning probe to a position X 1 away from the initialization position X 1 =0 and the second carriage moves the second tuning probe to a position X 2 away from the initialization position X 2 =0.
5. The load pull tuner-waveguide-to-wafer-probe adapter assembly of claim 1 ,
wherein
the carriages are moved by remotely controlled stepper motors, appropriate gear and motor control software running in a PC controller.
6. The load pull tuner-waveguide-to-wafer-probe adapter assembly of claim 1 ,
wherein
the tuning probes are inserted and moving inside the slots without contacting the waveguide walls.