Meaning
Measurement sensors designed to detect electromagnetic energy from all directions with equal sensitivity provide precise field intensity data. Using an isotropic electric field probe, test engineers can monitor the strength of radio-frequency fields in an anechoic chamber during susceptibility testing. This instrument prevents measurement errors that would occur if the sensing antenna was directional.
Sensor Configuration
Orthogonal arrangement of three independent sensor elements allows the device to capture the total vector sum of the electric field. This physical setup of the isotropic electric field probe guarantees that the rotation of the probe does not affect the reported field strength. The signal from each element is converted to an optical signal before being sent to the controller.
This configuration prevents the measurement cable from distorting the electromagnetic fields. Fiber optic lines are used because they do not reflect RF energy or create parasitic currents.
Calibration Requirement
Annual testing against a known laboratory standard is necessary to maintain the accuracy of the probe. Each isotropic electric field probe has a set of correction factors for different frequency bands stored in its internal memory. These values are applied automatically by the testing software during susceptibility runs.
This process ensures that the measurements remain traceable to national standards.
Field Measurement
Monitoring the generated fields in the quiet zone ensures that the device under test is exposed to the correct level of stress. Placing the isotropic electric field probe near the target board confirms that the radiation meets the requirements of the test plan. This verification is a key step in certified safety testing for consumer electronics.
