MegiQ VNA04 Series, Руководство пользователя

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VNA0440 – VNA0440e
VNA0460 – VNA0460e
user manual V3.1
www.megiq.com
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The calibration data is then used during the measurement to Normalize the data to become
independent of the test setup and the results are the characteristics of the DUT without the
influence of the test setup.
Device independent calibration
The calibration data of the VNA04x0 is normalized to the port level. This means that this
data is independent of the hardware and is applicable to any VNA that is used in the
measurement. It is well possible to perform calibration with one VNA04x0 unit and swap
this for another VNA04x0 and continue the measurements.
OSLT calibration
For calibration the MegiQ VNA software uses these impedances and connection:
•
Open : a well defined open circuit end.
•
Short : a well defined short circuit end.
•
Load : a precision impedance of 50 Ohm.
•
Through : for two-port measurement a well defined through connection between the
two ports.
This calibration scheme is often called OSLT or SOLT.
During a calibration procedure each of these terminations is connected in turn and the
software makes calibration measurements for each termination.
A set of these impedances for calibration is called a Calibration Kit or Calkit. They can
be of different types: SMA Calkit, N Calkit, UFL Calkit, Balanced Calkit etc. It depends
on your setup, with which connector type you can get closest to the DUT, which Calkit to
use. For small microwave devices the UFL connector is often the most appropriate to use.
For multi-port measurement the MegiQ VNA also measures the isolation between the
ports with a Load termination on both cable ends. They do not need to be of as high quality
as the Load termination during the Load calibration.
12-term normalization
For 2-port measurements it is important that all properties of the test setup are normalized
out of the results. During the calibration of a 2-port measurement the VNA collects 12
different characteristics of the test setup: 2 x Open, 2 x Short, 2 x Load, 2 x Through, 2 x
Isolation and 2 x the impedance of the receiving port that is connected to a source port.
These results are used in a 12-term normalization to normalize the DUT characteristics
as if it was sourced and terminated with a perfect 50 Ohm impedance.