User Guide
UG-1462
Rev. 0 | Page 9 of 18
MEASURING SWITCH PERFORMANCE
Figure 1 shows the EVAL-ADGM1004SDZ connection diagram.
Apply a VDD supply (V
DD
) to the EVAL-ADGM1004SDZ to
measure the performance of the switch. The links are set
according to the switch under test (see Table 4). After selecting
the desired channel and the state of the channel, use a network
analyzer to collect the switch performance data. Terminate the
RFx edge connectors of unused switch channels to 50 Ω loads to
achieve the full performance of the channel under test.
The EVAL-ADGM1004SDZ comes with the CALIBRATION
THRU calibration transmission line on the PCB. This calibration
transmission line removes the insertion loss and phase offset of
the PCB transmission lines connecting to the switch from the
measurement. Figure 7 shows the calibration transmission line,
and Figure 8 shows the calibration transmission line insertion
loss and return loss up to 16 GHz. The calibration transmission
line is exactly the same length as the distance from any one RFx
connector to the RFx pin of the device, plus the distance from
the RFC connector to the RFC pin of the device (see Label A
and Label B in Figure 9).
17
271
-006
Figure 7. EVAL-ADGM1004SDZ Calibration Transmission Line for PCB
Insertion Loss and Phase Offset Correction
0
–3.0
0
–50
–40
–30
–20
–10
–2.5
–2.0
–1.5
–1.0
–0.5
0
2.5
5.0
7.5
10.0
12.5
15.0
IN
SER
T
IO
N
L
O
SS
(d
B
)
RE
T
URN
L
O
S
S
(d
B)
FREQUENCY (GHz)
S(2,1)
S(1,1)
17
271
-00
7
Figure 8. Calibration Transmission Line Insertion Loss (S(2,1)) and
Return Loss (S(1,1))
Figure 9 shows the calibration transmission line length. All RF
traces connecting to the
are of equal length.
1
727
1-
0
08
A
B
Figure 9. Length of A + B Equal to Length of Calibration Transmission Line
To de-embed the PCB calibration transmission line insertion
loss from the entire switch insertion loss board measurement
(the RF1 to RFC path), divide the S(2,1) of measured data by
the |S(2,1)| of the calibration transmission line. To perform this
de-embedding using the network analyzer at the time of the
measurement or after the measurement, use individual
measurement data files. Refer to the Network Analyzer
Calibration Procedure section for more information.
Use the network analyzer port extension function to de-embed
the phase offset introduced by the PCB calibration transmission
lines. The port extension method uses time delay offset values
for phase correction. To perform this de-embedding, enter the
time delays into the port extension menu on the network
analyzer corresponding to the phase offset introduced from an
RF edge connector to the RFx pin of the
shows an example of these phase offsets on a typical switch
measurement, labeled as A and B. Both A and B are identical in
length, and can be calculated by measuring the time delay of the
calibration transmission line and dividing it by 2.
