VNA and method for addressing transmission line effects in VNA measurement data
View Patent ↗In one embodiment, a vector network analyzer (VNA) comprises a plurality of ports for coupling to a device under test (DUT), at least one reference receiver for measuring signals associated with the DUT, and logic for processing measurement data from the at least one reference receiver to compensate for transmission line effects, wherein the logic for processing evaluates a function, of several controllable variables, that is a sum of multiple transmission line models, wherein each of the controllable variables is related to a respective transmission line length associated with a corresponding transmission line model.
1. A vector network analyzer (VNA), comprising:
a plurality of ports for coupling to a device under test (DUT);
at least one reference receiver for measuring signals associated with said DUT; and
logic for processing measurement data from said at least one reference receiver to compensate for transmission line effects, wherein said logic for processing evaluates a function, of several controllable variables, that is a sum of multiple transmission line models, wherein each of said controllable variables is related to a respective transmission line length associated with a corresponding transmission line model.
2. The VNA of claim 1 wherein said function calculates a transmission line loss that occurs between at least one of said plurality of ports and said DUT.
3. The VNA of claim 1 wherein said function calculates an amount of transmission line delay that occurs between at least one of said plurality of ports and said DUT.
4. The VNA of claim 1 wherein said function calculates the amount of transmission delay that occurs within an adapter.
5. The VNA of claim 1 wherein one of said transmission line models is a coaxial transmission line model.
6. The VNA of claim 5 wherein said coaxial transmission line model is characterized by the following equation:
G c (ƒ)=ε r .
7. The VNA of claim 5 wherein said coaxial transmission line model is characterized by the following equation:
F c (ƒ)= K √{square root over (ƒ)}.
8. The VNA of claim 1 wherein one of said transmission line models is a rectangular waveguide transmission line model.
9. The VNA of claim 8 wherein said rectangular waveguide transmission line model is characterized by the following equation:
G
wg
(
f
)
=
ɛ
r
[
1
-
(
f
c
f
)
2
]
.
10. The VNA of claim 8 wherein said rectangular waveguide transmission line model is characterized by the following equation:
F
wg
(
f
)
=
π
f
μ
0
ρ
c
b
λ
0
2
(
ɛ
0
μ
0
)
[
1
+
2
b
a
(
λ
0
2
a
)
2
1
-
(
λ
0
2
a
)
2
]
.
11. The VNA of claim 1 wherein one of said transmission line models is microstrip transmission line model.
12. The VNA of claim 11 wherein said microstrip transmission line model is characterized by the following equation:
G
m
s
(
f
)
=
[
1
-
1
-
ɛ
re
ɛ
r
1
+
(
f
f
p
)
m
]
.
13. The VNA of claim 11 wherein said microstrip transmission line model is characterized by the following equations:
F
m
s
(
f
)
=
α
c
+
α
d
α
c
=
{
1.38
A
R
s
hZ
om
(
32
-
(
w
c
/
h
)
2
32
+
(
w
c
/
h
)
2
)
w
/
h
≤
1
6.1
*
10
-
5
A
R
s
Z
om
ɛ
ref
h
[
(
w
c
/
h
)
+
0.667
(
w
c
/
h
)
(
w
c
/
h
)
+
1.444
]
w
/
h
≥
1
α
d
=
{
4.34
(
1
υ
0
ωɛ
r
tan
(
δ
)
ɛ
ref
-
1
ɛ
ref
(
ɛ
r
-
1
)
)
w
/
h
≤
1
27.3
ɛ
r
ɛ
r
-
1
(
ɛ
ref
-
1
ɛ
ref
)
(
tan
(
δ
)
λ
0
)
w
/
h
≥
1
.
14. A method of operating a vector network analyzer (VNA), comprising:
generating measurement data by said VNA;
evaluating a function that is a sum of multiple transmission models using multiple variables, wherein each of said multiple variables is related to a respective transmission line length associated with a corresponding transmission line model;
processing said measurement data in response to said evaluating; and
compensating for transmission line effects in subsequent measurements by said VNA.
15. The method of claim 14 wherein said processing comprising:
performing amplitude compensation upon said measurement data.
16. The method of claim 14 wherein said processing comprises:
providing phase compensation to said measurement data.
17. The method of claim 14 wherein said multiple transmission line models include a coaxial transmission line model, a rectangular waveguide transmission line model, and a microstrip transmission line model.
18. The method of claim 14 wherein said multiple transmission line models include multiple models with different physical characteristics.
19. A system, comprising:
means for generating a stimulus signal for application to a device under test (DUT);
means for applying said signal to said DUT;
means for measuring signals associated with said DUT; and
means for processing measurement data from said means for measuring to compensate for transmission line effects, wherein said means for processing evaluates a function, of several controllable variables, that is a sum of multiple transmission line models, wherein each of said controllable variables is related to a respective transmission line length associated with a corresponding transmission line model.
20. The system of claim 19 wherein said means for processing performs amplitude compensation upon said measurement data.
21. The system of claim 19 wherein said means for processing provides phase compensation to said measurement data.
22. The system of claim 19 wherein said multiple transmission line models include a coaxial transmission line model, a rectangular waveguide transmission line model, and a microstrip transmission line model.