ES User’s Guide 3-25
Making Measurements
Measuring S-Parameters using a Two-Port Calibration
Calibrating for Noninsertable Devices
A noninsertable device is one that cannot be inserted in place of a
zero-length through-standard. It has the same connectors on each port
(type and sex) or has a different type of connector on each port (SMA on
one port, and type-N on the other, for example). The following two
calibration methods are available for noninsertable devices:
• swap equal adapters
• modify the calibration kit definition of the through standard
Method A: Swap Equal Adapters.
In the following example, the noninsertable device is type-N, with female
input and output connectors.
With this method, you use two precision matched adapters which are
“equal.” To be equal, the adapters must have the same match,
characteristic impedance (Z
0
), insertion loss, and electrical delay. The
adapters in most HP calibration kits have matched electrical lengths,
even if the physical lengths appear different.
NOTE For analyzers with 50 ohm input impedance only: in the 50 ohm type-N
calibration kit (HP 85032B), there are four equal adapters: two
APC-7 to type-N(f), and two APC-7 to type-N(m). To create adapter A in
the following example, connect an APC-7-to-type-N(f) adapter with an
APC-7 to type-N(m) adapter. To create adapter B, connect two
APC-7 to type-N(m) adapters.
NOTE By convention, cal kit labels in the analyzer indicate the sex of the port
with which they are used. For example, the default cal kit for the
analyzer is type-N female because the front panel RF ports are female
(the calibration standards, in turn, have male connectors).
1. Connect a test cable with type-N(m) connectors to port 2.
2. To select calibration kits for both ports, press
, and use the front panel knob or the keys to
highlight Port 1 in the display’s table. Press . Now,
highlight Port 2 and again press .
3. Connect adapter A (type-N(m) to type-N(f)) to port 1.
CAL
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