Network Analyzer Error Sources with Coaxial Probe Measurements (Opt. 004)

The effect of network analyzer error sources can be calculated as follows:

= N x S

where

is the error (or delta epsilon)

N is network analyzer uncertainty (in linear terms)

S is the sensitivity number (absolute value)

For example, assume PTFE (r=2.1) is measured at 10 GHz with a LOAD/AIR/SHORT calibration. At 10 GHz the fixed load/probe directivity contribution would be about 0.05. At 10 GHz for r=2.1 the sensitivity is 8.1.

The measurement error due to the fixed load/probe directivity would be computed as:

= 0.05 x 8.1 = 0.4

Note that this is not total measurement error, only the portion due to the fixed load/probe directivity.