Radiated Susceptibility

Radiated susceptibility testing is a critical aspect of electromagnetic compatibility (EMC) assessments. Radiated susceptibility testing aims to determine how susceptible a device or system is to interference from electromagnetic fields. The test helps ensure that electronic devices and systems can operate reliably in their intended electromagnetic environment without degradation in performance or functionality.

Testing Standards

IEC 61000-4-3: This is the basic standard specifies the test methods and requirements for radiated electromagnetic fields including equipment, evaluation criteria.

Test Setup

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The test setup typically involves the following components:

• Test Chamber: An anechoic chamber or shielded room is used to minimize reflections and external noise. An anechoic chamber is preferred for its ability to absorb reflected signals and simulate an open environment.

• Antenna: A transmitting antenna (usually a log-periodic or biconical antenna) generates the electromagnetic field. Its placement and alignment are crucial for accurate testing.

• Equipment Under Test (EUT): The equipment or system being tested is positioned at a specified distance from the antenna, usually within the chamber’s test volume.

• Measurement Equipment: Includes a field strength meter or a spectrum analyzer to measure the field strength and frequency of the incident electromagnetic field.

• Support Equipment: This may include signal generators, amplifiers, and control systems to modulate and manage the electromagnetic field.

 

Test Procedure

The radiated susceptibility test generally follows these steps:

1. Preparation:

   • Pre-Conditioning: The EUT is operated under normal conditions to ensure it is in a stable operating state before testing.

   • Positioning: The EUT is placed at a defined distance from the transmitting antenna, typically 1 to 3 meters, depending on the test standard.

2. Field Generation:

   • The transmitting antenna is used to create a uniform electromagnetic field. The field strength is varied according to the test specifications, and the frequency is swept across the relevant range.

3. Testing:

   • The EUT is exposed to the electromagnetic field at different frequencies and field strengths.

   • Monitoring and data collection are performed to detect any performance degradation or malfunction in the DUT.

4. Evaluation:

   • The EUT’s performance is evaluated based on predefined criteria. This may involve checking for operational faults, malfunctions, or deviations from normal performance.

Key Parameters

• Field Strength: Measured in volts per meter (V/m), indicating the intensity of the electromagnetic field.

• Frequency Range: The range of frequencies to which the EUT is exposed, usually spanning from a few kilohertz to several gigahertz.

• Test Duration: The length of time the EUT is exposed to the electromagnetic field, which can vary based on the standard and specific requirements.

• Distance: The distance between the antenna and the DUT, which affects the field strength and uniformity.

Evaluation Criteria

The DUT is assessed based on its performance during the test. Common evaluation criteria include:

• Functional Performance: Whether the DUT continues to perform its intended functions correctly.

• Error Rates: Any increase in error rates or malfunction incidents during exposure.

• Data Integrity: For communication devices, the integrity of data transmission may be checked.

Reporting

Test results are documented in a detailed report that includes:

• Test Setup Details: Describes the equipment, configuration, and environment.

• Test Conditions: Specifies field strength, frequency range, and exposure duration.

• Results: Provides observations, any issues encountered, and performance metrics.