Agilent Technologies 8510 - Manual (Page 18)

18
S
11
A,B,C and S
22
A,B,C
S
11
A, B,C and S
22
A,B,C correspond to the S
11
and
S
22
reflection calibrations for port 1 and port 2
respectively. These three classes are used by the
Agilent 8510 to solve for the systematic errors;
directivity, source match, and reflection tracking.
The three classes used by the 7-mm cal kit are
labeled “short,” “open,” and “loads.” “Loads” refers
to a group of standards which is required to com-
plete this standard class. A class may include a set
of standards of which there is more than one
acceptable selection or more than one standard
required to calibrate the desired frequency range.
Table 2 contains the class assignment for the WR-
62 waveguide cal kit. The
1 /
8
λ offset short (stan-
dard #1) is assigned to S
11
A. The 3 /
8
λ offset short
(standard #2) is assigned to S
11
B. The matched
load (standard #3) is assigned to S
11
C.
Forward transmission match and thru
Forward Transmission (Match and Thru) classes
correspond to the forward (port 1 to port 2) trans-
mission and reflection measurement of the
“delay/thru” standard in a FULL 2-PORT or ONE-
PATH 2-PORT calibration. During measurement
calibration the response of the “match” standard is
used to find the systematic Load Match error term.
Similarly the response of the thru standard is used
to characterize transmission tracking.
The class assignments for the WR-62 waveguide cal
kit are as follows. The thru (standard #4) is
assigned to both FORWARD TRANSMISSION and
FORWARD MATCH.
Reverse transmission match and thru
Reverse Transmission (Match and Thru) classes
correspond to the reverse transmission and reflec-
tion measurement of the “delay/thru” standard.
For S-parameter test sets, this is the port 2 to port 1
transmission path. For the reflection/transmission
test sets, the device is reversed and is measured in
the same manner using the forward transmission
calibration.
The class assignments for the WR-62 waveguide cal
kit are as follows. The thru (Standard #4) is
assigned to both REVERSE TRANSMISSION and
REVERSE MATCH.
Isolation
Isolation is simply the leakage from port 1 to port 2
internal to the test set.
To determine the leakage signals (crosstalk), each
port should be terminated with matched loads
while measuring S
21
and S
12
.
The class assignments for forward and reverse iso-
lation are both loads (standard #3).
Frequency response
Frequency Response is a single class which corre-
sponds to a one-term error correction that charac-
terizes only the vector frequency response of the
test configuration. Transmission calibration typi-
cally uses a “thru” and reflection calibration typi-
cally uses either an “open” or a “short.”
Note
The Frequency Response calibration is not a sim-
ple frequency normalization. A normalized
response is a mathematical comparison between
measured data and stored data. The important dif-
ference is, that when a standard with non-zero
phase, such as an offset short, is remeasured after
calibration using Frequency Response, the actual
phase offset will be displayed, but its normalized
response would display zero phase offset (meas-
ured response minus stored response).
Therefore, the WR-62 waveguide calibration kit class
assignment includes standard #1, standard #2, and
standard #4.