Hybrid digital electronic tuner
View Patent ↗A hybrid digital electronic tuner (HDET) uses a modified forward signal power injection technique, a variance of a prior art Gamma Boosting Unit (GBU) technique, cascaded with a digital, PIN diode based, electronic tuner, all integrated in the same low loss parallel plate airline (slabline) to create a compact hybrid tuner unit able of generating thousands of high reflection factors (|Gamma|≥1) at millisecond tuning speed.
1. A hybrid digital electronic impedance tuner (HDET) comprising two modules,
a) an active tuner module, and
b) a passive tuner module,
wherein
the active module comprises two ports, an input (test) port and an output (idle) port, and
a slotted airline (slabline) between the ports, two directional signal couplers (wave-probes) and an amplifier;
wherein
the slabline comprises metallic, grounded sidewalls, a center conductor between the ports and the two wave-probes, of which one is fixed and one is mobile,
and wherein
each wave-probe comprises a coupled port and an isolated port,
and wherein
the mobile wave-probe is attached on an adjustable vertical axis of a mobile carriage, said the vertical axis controlling the penetration of the mobile wave-probe into the slot of the slabline,
and wherein
the carriage slides across the length of the slabline;
and wherein
the passive tuner module comprises a multitude of RF electronic switches (PIN diodes), and is incorporated in the section of the slabline between the active module and the output port.
2. The tuner of claim 1 , wherein the RF electronic switches of the passive module are inserted along the section of the slabline between the active tuner module and the output port, mounted between the bottom of the center conductor of the slabline and ground.
3. The tuner of claim 2 , whereby the wave-probes are inserted between the walls of the slabline and placed between the test port and the multitude of electronic switches.
4. The tuner of claim 3 , wherein the mobile wave-probe is mounted closest to the test port.
5. The tuner of claim 4 , wherein the coupled port of the mobile wave-probe is connected to the input port of the amplifier and the output port of the amplifier is connected to the coupled port of the fixed wave-probe, and
wherein
the isolated ports of both wave-probes are terminated with characteristic impedance.
6. The tuner of claim 5 whereby the position of the mobile carriage moving along the slabline and the position of the vertical axis are remotely controlled using gear, control processor and appropriate control software.
7. The tuner of claim 6 , whereby each of the multitude of electronic switches is DC biasable and RF grounded and individually controlled between the ON and OFF states using appropriate electronic control.
8. A calibration method for the tuner of claim 7 at a user defined frequency comprising the following steps:
a) the tuner is connected to a pre-calibrated vector network analyzer (VNA);
b) the mobile wave-probe is withdrawn, all electronic switches are set to OFF (open circuit) and s-parameters of the tuner are measured and saved in a matrix [S 0 ];
c) the mobile wave-probe is gradually inserted into the slabline and the carriage moved horizontally creating a multitude of active module states and the s-parameters of the tuner are measured and saved;
d) the mobile wave-probe is withdrawn and s-parameters of the tuner for all permutations of electronic switches between ON and OFF states are measured and saved;
e) the s-parameters of step d) are de-embedded (cascaded with the inverse matrix [S 0 ] −1 );
f) the s-parameters of steps c) and e) are cascaded in computer memory and saved in calibration file for later use.