Patent ID: 11863163
Assignee: nan
Field: Telecommunications (Electrical engineering)
Classification: CPC H  G | IPC H

Claim 3:
4. A small signal calibration method for the digital hybrid load pull tuner of claim 1 comprising the following steps:
a) calibrating the passive slide screw tuner, between the test port and the idle port of the slabline with the active tuner turned OFF,
wherein
a1) s-parameters between the test port and the idle port of the slabline are measured with the tuning probes withdrawn from the slabline, and saved as matrix [SP0]; s-parameters between the test port and the idle port of the slabline are measured for a multitude of horizontal XT and vertical YT positions of each individual tuning probe, all remaining probes having been withdrawn from the slabline, and saved as matrices [SP(XT, YT)];
a2) s-parameters of all tuning probes, except of the tuning probe closest to the test port, are de-embedded (cascaded with the inverse matrix [SP0]−1) and permutations of cascaded s-parameters of all tuning probes are calculated and saved;

b) calibrating the digital, closed loop active injection tuner, with the passive tuning probes withdrawn from the slabline, in two steps:
b1) calibrating the digital electronic tuner;
b2) calibrating the digital active injection closed loop;

wherein
b1) the digital electronic tuner is calibrated between its test the idle ports as follows:
b1.1) s-parameters are measured with all N>1 digital switches set to OFF (open) and saved as [SD0] matrix,
b1.2) each individual switch Di (1≤i≤N) is turned ON (closed), all other switches being set to OFF, and s-parameters are measured and saved in matrices [SDi];
b1.3) all s-parameter matrices [SDi], except for [SDI], are cascaded with the invers matrix [SD0]−1 and saved;
b1.4) all 2 N permutations of all s-parameter matrices in step b1.3) are generated in computer memory and saved as matrices [SDj] for (1≤j≤2N);
b2) the digital, active injection closed loop is calibrated as follows:
b2.1) the reflection factor S11 is measured at the test port of the slabline, with an OPEN connected to port #2 of the circulator, for a multitude of NX horizontal (XC) positions of the first carriage and NY vertical (YC) positions of the vertical axis of the first carriage and saved as S11 (XC, YC);
b2.2) the NX*NY reflection factors S11 (XC, YC) of step b2.1) are multiplied with the reflection factors S11 of the 2N s-parameter permutations of matrices [SDj] of step b1.4) and saved.