The Analyzer emits a test signal (stimulus) out of a port connected to the DUT. The frequency of the test signal changes in the specified range discretely from point to point. At each frequency point, the Analyzer simultaneously measures the magnitude and phase of the signal transmitted through and reflected from the DUT. These are compared with the magnitude and phase of the incident test signal. The Analyzer calculates the S-parameters of the DUT at each frequency point based on this comparison (See figure below).
S-parameter terms
The S-parameter is a relation between the complex magnitudes of two waves:
Providing the , except = 0, where denote the DUT port number.
In accordance with the measurement plan, the Analyzer performs a frequency sweep in one direction in a specified frequency range. Then, if needed, the Analyzer performs a frequency sweep in reverse direction in a specified frequency range. The frequency changes discretely, according to the number of measuring points specified. S-parameters of the DUT are measured for each measuring point.
1-port Analyzer has one measurement port which operates as a signal source and as a reflected signal receiver. That is why the Analyzer allows measuring only S11 parameter.
RNVNA can have up to 16 1-port Analyzers that allows to measure scalar scattering matrix:
For example:
For the measurement of S11, |S21|, ... , |S15.1|, |S16.1| parameters, test Port 1 will operate as a signal source. The incident and reflected waves will be measured by Port 1. The transmitted wave will be measured by Port 2, Port 3, ... Port16. For the measurement of |S12|, S22, ... , |S16.2| parameters, test Port 2 will operate as a signal source. The incident and reflected waves will be measured by Port 2. The transmitted wave will be measured by Port1, Port 3, ... Port16.
When a stimulus is applied to one of the test ports, the Analyzer measures S-parameters, which constitute one column in the S-parameter matrix. To have the full scattering matrix, the sixteen-port Analyzer applies a stimulus to all the test ports one after another.
