Method of measuring scattering parameters of device under test
A method of measuring scattering parameters (S-parameters) of a device under test (DUT) is provided in the present disclosure. The S-parameters of the DUT with two connectors of different standards may be obtained without performing a full two-port calibration using an adapter kit. Two one-port calibrations are performed in the present disclosure to build two error models, the first one of which includes the characteristics of one-port of a network analyzer and a cable, the second one of which further includes the characteristics of the DUT. Therefore, the characteristics of the DUT may be obtained by removing the characteristics of the first error model from the second error model.
1. A method of measuring scattering parameters (S-parameters) of a device under test (DUT), adapted for measuring a DUT having a first connector and a second connector, comprising:
performing a first one-port calibration on a port-1 of a network analyzer to obtain a first set of calibration parameters;
connecting the first connector of the DUT to the port-1 and performing a second one-port calibration through the second connector of the DUT on the port-1 to obtain a second set of calibration parameters associated with a reference plane in correspondence to the second connector of the DUT; and
performing arithmetic operations using the first set of calibration parameters and the second set of calibration parameters to obtain the S-parameters of the DUT.
2. The method of measuring the S-parameters of the DUT according to claim 1 , wherein the DUT is an adapter having the first and the second connectors of different standards.
3. The method of measuring the S-parameters of the DUT according to claim 1 , wherein the process of performing arithmetic operations using the first set of calibration parameters and the second set of calibration parameters to obtain the S-parameters of the DUT further comprises of using the following formula to compute the S-parameters of DUT:
S
11
=
E
DF
′
-
E
DF
E
RF
+
E
SF
(
E
DF
′
-
E
DF
)
;
S
21
S
12
=
E
RF
′
(
1
-
E
SF
S
11
)
2
E
RF
;
and
S
22
=
E
SF
′
-
E
SF
S
21
S
12
1
-
E
SF
S
11
;
wherein the parameters S 11 , S 12 , S 21 , and S 22 represent the S-parameters of the DUT; EDF representing the forward directivity error associated with the first set of calibration parameters and E′DF representing the forward directivity error associated with the second set of calibration parameters; ESF representing the forward source error associated with the first set of calibration parameters and E′SF representing the forward source error associated with the second set of calibration parameters; ERF representing the forward reflection tracking error associated with the first set of calibration parameters and E′RF representing the forward reflection tracking error associated with the second set of calibration parameters.
4. The method of measuring the S-parameters of the DUT according to claim 1 , wherein the process of performing arithmetic operations using the first set of calibration parameters and the second set of calibration parameters to obtain the S-parameters of the DUT further comprises mathematically removing the first set of calibration parameters from the second set of calibration parameters to obtain the S-parameters of the DUT.
5. The method of measuring the S-parameters of the DUT according to claim 1 , wherein performing the first one-port calibration on the port-1 of the network analyzer to obtain the first set of calibration parameters further comprises of utilizing a first Short calibration kit, a first Open calibration kit, and a first Load calibration kit, with each being adaptable to port-1 in the one-port calibration of the network analyzer.
6. The method of measuring the S-parameters of the DUT according to claim 5 , wherein performing the second one-port calibration on the port-1 of the network analyzer further comprises of utilizing a second Short calibration kit, a second Open calibration kit, and a second Load calibration kit, with each being adaptable to the second connector of the DUT in the one-port calibration of the network analyzer.
7. The method of measuring the S-parameters of the DUT according to claim 1 , wherein the first set of calibration parameters comprises of three systematic error components and the three systematic error components further comprise of a forward directivity error, a forward source match error, and a forward reflection tracking error.
8. The method of measuring the S-parameters of the DUT according to claim 1 , wherein the second set of calibration parameters comprises of three systematic error components and the three systematic error components further comprise of a forward directivity error, a forward source match error, and a forward reflection tracking error, wherein these systematic errors components comprises the characteristics of the DUT.
9. The method of measuring the S-parameters of the DUT according to claim 1 , wherein the network analyzer performs the first and the second one-port calibrations to obtain the first and the second sets of calibration parameters without pre-loaded the calibration parameters.