Method of calibrating a setup

Patent metadata

Field	Value
Publication number	US-11428770-B2
Application number	US-202016834733-A
Country	US
Kind code	B2
Filing date	Mar 30, 2020
Priority date	Mar 30, 2020
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A method of calibrating a setup comprises: performing at least one calibration of the setup, thereby obtaining calibration data; setting a quantity representing forward tracking to be equal with a quantity representing reverse tracking; solving a system of equations having at least an unknown quantity representing the forward tracking or the reverse tracking, thereby obtaining at least one equation having the unknown quantity squared; creating based on the calibration data obtained two phase over frequency relationships for the respective quantity; determining two lines having a linear change in phase over frequency for the phase over frequency relationships created; extrapolating the lines determined to a frequency of 0 Hz; and determining the respective quantity by selecting one line of the lines extrapolated that is closer to a phase of zero, 2π or a multiple thereof at the frequency of 0 Hz.

First claim

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of calibrating a setup while taking delay and loss between an analyzer and a calibration plane in the setup into account, wherein the method comprises:
performing at least one calibration of the setup by three calibration standards or by a calibration kit encompassing the three calibration standards, thereby obtaining calibration data;
setting a quantity representing forward tracking to be equal with a quantity representing reverse tracking;
solving a system of equations having at least an unknown quantity representing the forward tracking or the reverse tracking, thereby obtaining at least one equation having the unknown quantity squared;
creating based on the calibration data obtained two phase over frequency relationships for the respective quantity, wherein the two phase over frequency relationships are assigned to the results of the square root of the unknown quantity squared when solving the at least one equation;
determining two lines having a linear change in phase over frequency for the two phase over frequency relationships created;
extrapolating the two lines determined to a frequency of 0 Hz; and
determining the respective quantity by selecting one line of the two lines extrapolated that is closer to a phase of zero, 2π or a multiple thereof at the frequency of 0 Hz,
wherein a 9-term error model for calibration of at least two ports is provided that uses the respective quantity determined instead of quantities obtained from a 3-term error model.

2. The method according to claim 1 , wherein the steps, except for the step of performing the at least one calibration, are performed in a fully automatic manner.

3. The method according to claim 1 , wherein a respective function value of the two lines is determined at the frequency of 0 Hz, and wherein the respective function value determined is compared with zero, 2π or a multiple thereof in order to determine the quantity.

4. The method according to claim 1 , wherein waves in forward direction and waves in reverse direction are determined at the calibration plane based on the respective waves measured at the analyzer and the respective quantity determined.

5. The method according to claim 1 , wherein the system of equations comprises at least three equations.

6. The method according to claim 1 , wherein the calibration is done without performing a loss calibration by a power meter.

7. The method according to claim 1 , wherein an absolute phase calibration of the analyzer is performed in order to extend the absolute phase calibration to the calibration plane.

8. The method according to claim 1 , wherein at least one of a port match calibration and a source match calibration is done, and wherein a group delay measurement is performed subsequently.

9. The method according to claim 8 , wherein the group delay measurement is done by a one tone measurement or a two tone measurement.

10. The method according to claim 1 , wherein the three calibration standards used for the calibration correspond to an open standard, a short standard and a match standard or wherein the three calibration standards used for the calibration correspond to an offset short standard, a short standard and a match standard.

11. The method according to claim 1 , wherein the analyzer is a vector network analyzer.

12. A method of calibrating a setup while taking delay and loss between an analyzer and a calibration plane in the setup into account, wherein the method comprises:
performing at least one calibration of the setup by three calibration standards or by a calibration kit encompassing the three calibration standards, thereby obtaining calibration data;
setting a quantity representing forward tracking to be equal with a quantity representing reverse tracking;
solving a system of equations having at least an unknown quantity representing the forward tracking or the reverse tracking, thereby obtaining at least one equation having the unknown quantity squared;
creating, based on the calibration data obtained, two phase over frequency relationships for the respective quantity, wherein the two phase over frequency relationships are assigned to the results of the square root of the unknown quantity squared when solving the at least one equation;
determining two lines having a linear change in phase over frequency for the two phase over frequency relationships created;
extrapolating the two lines determined to a frequency of 0 Hz; and
determining the respective quantity by selecting one line of the two lines extrapolated that is closer to a phase of zero, 2π or a multiple thereof at the frequency of 0 Hz, and
wherein it is assumed that the connection between the analyzer and the calibration plane is provided by at least one passive component having reciprocal characteristics with regard to signal processing.

13. A method of calibrating a setup while taking delay and loss between an analyzer and a calibration plane in the setup into account, wherein the method comprises:
performing at least one calibration of the setup by three calibration standards or by a calibration kit encompassing the three calibration standards, thereby obtaining calibration data;
setting a quantity representing forward tracking to be equal with a quantity representing reverse tracking;
solving a system of equations having at least an unknown quantity representing the forward tracking or the reverse tracking, thereby obtaining at least one equation having the unknown quantity squared;
creating, based on the calibration data obtained, two phase over frequency relationships for the respective quantity, wherein the two phase over frequency relationships are assigned to the results of the square root of the unknown quantity squared when solving the at least one equation;
determining two lines having a linear change in phase over frequency for the two phase over frequency relationships created;
extrapolating the two lines determined to a frequency of 0 Hz; and
determining the respective quantity by selecting one line of the two lines extrapolated that is closer to a phase of zero, 2π or a multiple thereof at the frequency of 0 Hz,
wherein a port match calibration and a source match calibration are done, wherein a group delay measurement is performed subsequently, and
wherein the group delay measurement is done by a two tone measurement such that the analyzer generates two sinusoidal signals with a given frequency difference, resulting in a two tone signal which is used as an excitation signal for the respective measurement.

Assignees

• Rohde & Schwarz

Inventors

• Schultheis Jan-Patrick
• Held Werner

Classifications

• G01R23/175

  by delay means, e.g. tapped delay lines · CPC title

• G06F17/12

  Simultaneous equations {, e.g. systems of linear equations} · CPC title

• G01R27/32

  in circuits having distributed constants {, e.g. having very long conductors or involving high frequencies} · CPC title

• G01R27/28

  Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response (in line transmission systems H04B3/46) · CPC title

• G01R27/06

  Measuring reflection coefficients; Measuring standing-wave ratio · CPC title