Balanced device characterization including test system calibration

2:

• The method of claim 1, wherein the VNA measurement system comprises a multiport VNA and a hybrid junction coupler, the hybrid junction coupler being connected to a pair of test ports of the multiport VNA, the system optionally further comprising a test fixture, the test fixture being connected between outputs of the hybrid junction coupler and another pair of test ports of the multiport VNA, wherein the uncalibrated portion of the VNA measurement system comprises the hybrid-junction coupler and the optional test fixture.

4:

• The method of claim 3, wherein characterizing the uncalibrated portion of the VNA measurement system comprises characterizing a hybrid junction coupler connected between test ports of the multiport VNA and input ports of the balanced DUT, and wherein de-embedding the uncalibrated portion comprises de-embedding the characterized hybrid junction coupler.

5:

• The method of claim 4, wherein characterizing the uncalibrated portion of the VNA measurement system further comprises characterizing a test fixture connected between outputs of the hybrid junction coupler and other test ports of the multiport VNA, the test fixture interfacing the balanced DUT to the multiport VNA and the hybrid junction coupler for measuring, and wherein de-embedding the uncalibrated portion further comprises de-embedding the characterized test fixture.

6:

• The method of claim 4, wherein characterizing the hybrid junction coupler comprises determining S-parameters that represent an operational performance of the hybrid junction coupler over a frequency range of interest.

7:

• The method of claim 4, wherein the characterizing the hybrid junction coupler comprises one or more of measuring S-parameters of the hybrid junction coupler using either the calibrated multiport VNA or another VNA, employing S-parameters for the hybrid junction coupler supplied by a manufacturer of the hybrid junction coupler, and modeling a performance of the hybrid junction coupler using a computer model and extracting S-parameters from the modeled performance.

8:

• The method of claim 4, wherein characterizing the hybrid junction coupler comprises further calibrating the multiport VNA with the hybrid junction coupler connected to the multiport VNA, the further calibration being performed at output-ports of the hybrid junction coupler, such that error terms of an error model for the multiport VNA calibration and error terms for an error model of the multiport VNA and hybrid junction coupler calibration are separately determined.

9:

• The method of claim 8, wherein S-parameters of the characterized hybrid junction coupler are determined from a difference between the error terms of the multiport VNA calibration and the error terms of the multiport VNA and hybrid junction coupler calibration.

11:

• The method of claim 10, fiber comprising:
• converting the de-embedded S-parameters into mixed mode S-parameters using modal decomposition.

12:

• The method of claim 10, wherein characterizing the hybrid junction coupler comprises one or more of measuring S-parameters of the hybrid junction coupler using the calibrated multiport VNA or another VNA, employing S-parameters for the hybrid junction coupler supplied by a manufacturer of the hybrid junction coupler, and modeling a performance of the hybrid junction coupler using a computer model and extracting S-parameters from the modeled performance of the hybrid junction coupler.

13:

• The method of claim 10, wherein characterizing the hybrid junction coupler comprises further calibrating the multiport VNA with the hybrid junction coupler connected to the multiport VNA, the further calibration being performed at output ports of the hybrid junction coupler, such that error terms of an error model for the multiport VNA calibration and error terms for an error model of the multiport VNA and hybrid junction coupler calibration are separately determined.

14:

• The method of claim 13, wherein S-parameters of the characterized hybrid junction coupler are determined from a difference between the error terms of the multiport VNA calibration and the error terms of the multiport VNA and hybrid junction coupler calibration.

15:

• The method of claim 10, wherein characterizing the test fixture when used comprises producing S-parameters that represent an operational performance of the test fixture, the S-parameters being produced from one or more of measurements of the S-parameters, test fixture vendor supplied S-parameter data, and modeled S-parameter data using a computer model of the test fixture, wherein the S-parameters measurements are produced using either the calibrated multiport VNA or another VNA.

16:

• The method of claim 10, wherein measuring S-parameters of the balanced DUT comprises measuring output signals at output ports of the balanced DUT and output reflected signals at input ports of the hybrid junction coupler during multiple frequency sweeps with the multiport VNA.

17:

• The method of claim 16, wherein measuring output signals at output ports of the balanced DUT comprises applying a balanced signal to input ports of the balanced DUT, the balanced signal comprising a common mode signal applied during a first frequency sweep, and a differential mode signal applied during a second frequency sweep.

18:

• The method of claim 10, wherein de-embedding the characterized hybrid junction coupler comprises producing a first set of de-embedded S-parameters from the measured S-parameters and S-parameters of the characterized hybrid junction coupler, the produced first set comprising measured S-parameters corrected for effects of the hybrid junction coupler.

19:

• The method of claim 18, wherein de-embedding the characterized test fixture comprises producing a second set of de-embedded S-parameters from the first set and S-parameters of the characterized test fixture, the produced second set comprising measured S-parameters corrected for effects of the hybrid junction coupler and the test fixture, such that the second set of de-embedded S-parameters are error-corrected measured S-parameters for the balanced DUT.

21:

• The test system of claim 20, wherein the uncalibrated portion comprises a hybrid junction coupler interfaced between the multiport VNA and the balanced DUT, and a test fixture that is optionally used to interface the hybrid junction coupler and the multiport VNA to the balanced DUT.

22:

• The test system of claim 20, wherein the instructions of the computer program comprise instructions that implement calibrating the multiport VHA, characterizing the uncalibrated portion of the test system, measuring S-parameters of the balanced DDT with the calibrated multiport VNA, and de-embedding the uncalibrated portion characterization from the S-parameter measurements, such that the do-embedded measured S-parameter of the balanced DUT result.

23:

• The test system of claim 22, wherein the instructions of the computer program further comprise instructions that implement converting the de-embedded measured S-parameters into mixed mode S-parameters using modal decomposition.

24:

• The test system of claim 20, wherein the multiport VNA comprises a processor, the processor executing the computer program.

25:

• The test system of claim 20, further comprising an auxiliary computer processor external to the multiport VNA, the auxiliary computer processor executing the computer program.

26:

• The test system of claim 20, wherein a balanced signal is used to drive the balanced DUT when S-parameters of the balanced DUT are measured, the balanced signal comprising a common mode signal applied to the balanced DUT during a first frequency sweep of the multiport VNA, and a differential mode signal applied to the balanced DUT during a second frequency sweep of the multiport VNA.

27:

• The test system of claim 20, wherein the balanced signal comprising a common mode signal applied to the balanced DUT during a first frequency sweep of the multiport VNA, and a differential mode signal applied to the balanced DUT during a second frequency sweep of the multiport VNA.

29:

• The method of claim 28, further comprising converting the de-embedded single-ended S-parameters for the DUT into mixed mode S-parameters for the DUT.

30:

• The method of claim 28, wherein the component of the VNA test system that corrupts the measurements comprises a hybrid junction coupler used to produce the balanced signal and a test fixture when optionally used to interface the balanced DUT with the VNA test system.