Why is the linearity of E441x, E930x, E932x and E/V/W8486A Power Sensors not tested per sensor’s dynamic range?

In actuality, there is little necessity to test linearity of those power sensors below -20dBm. Those power sensors’ ability to track applied power is linear up to approximately -20dBm due to the use of diode detector which has an inherently predictable square law response. The response only becomes non-linear above -20dBm thus requiring characterization.
 

Where there is non-compliance with the specified accuracy at low power levels, it is unlikely to be caused by the sensors’ linearity. In this situation, it is recommended to first confirm compliance with the sensors’ zero drift and noise specifications. Non-compliance can only be corrected by repair/replacement of the sensor module.