CISPR 25 (Section 6.5) RF Radiated Emissions Testing 

Overview of CISPR 25 Standard 

CISPR 25 is the key international standard for radiated and RF emissions testing in automotive EMC, ensuring electronics don’t interfere with vehicle radios or communications. 

Section 6.5 focuses on radiated emissions from subassemblies, requiring controlled, repeatable testing that reflects real-world conditions. Testing is done in an absorber-lined shielded enclosure (ALSE) to reduce reflections and external interference. 

The 2021 Edition covers emissions from 150 kHz to 2.5 GHz, using a ground plane and test harness. Emissions are measured with compliant antennas and a measuring receiver. 

CISPR 25 defines performance classes with emissions limits tailored to different automotive applications, enabling OEMs and suppliers to customize testing for specific vehicle platforms. Its detailed requirements for harness setup, antenna choice, and ground plane size ensure accurate, representative results. 

Importance of RF Radiated Emissions Testing 

RF and radiated emissions testing ensure automotive electronics don’t interfere with infotainment, navigation, or safety systems. As vehicles become more connected, this testing grows increasingly important. CISPR 25 helps engineers identify and resolve interference early. 

Following CISPR 25 Section 6.5 and using absorber-lined shielded enclosures supports EMC compliance for components, commercial vehicles, and passenger cars. The 150 kHz to 2.5 GHz range covers key bands like AM/FM, GPS, and wireless communications. 

CISPR 25 compliance aids risk management by enabling systematic evaluation and documentation of emissions, supporting certification, and reducing recalls or warranty claims. Its clear limits and performance classes facilitate communication with OEMs and regulators. 

Ultimately, RF emissions testing ensures reliable vehicle performance in real-world electromagnetic environments, not just in the lab. 

Key Features and Benefits of CISPR 25 Radiated Emissions Testing 

CISPR 25 is essential for validating emissions in automotive electronics. It requires testing in an absorber-lined shielded enclosure (ALSE) with a defined setup—including ground plane, test harness, receiver, and antennas—to ensure consistent, repeatable results. 

Detailed guidelines for EUT orientation, harness configuration, measurement uncertainty, and calibration enhance test reliability. Its data analysis and reporting standards support traceability and continuous design improvement. 

By following CISPR 25, manufacturers can demonstrate compliance with supply line radiated emissions, simplify certification, and build confidence with OEMs and end users. The standard’s flexibility also accommodates new technologies like electric vehicles and advanced infotainment systems. 

Risk Management and the Role of Testing 

CISPR 25 is vital for risk management, helping engineers identify emissions issues early, before they impact vehicle performance or customer satisfaction. Its structured procedures and performance classes enable benchmarking and continuous improvement. 

The standard covers emissions testing for vehicle modules, infotainment systems, and sensors—areas increasingly vulnerable as vehicles become more electrified and connected. Detailed setup and calibration ensure accurate, repeatable results for both power and signal leads. 

Integrating CISPR 25 into development helps manufacturers prevent recalls, lower warranty costs, and protect brand reputation while supporting innovation and regulatory compliance. 

Why Choose CISPR 25 for RF Radiated Emissions Testing? 

CISPR 25 is the global standard for RF and radiated emissions testing in automotive applications, trusted by OEMs and regulators. Its detailed procedures and use of absorber-lined shielded enclosures (ALSE) with multiple antennas ensure thorough emissions evaluation. 

A standardized setup—including ground plane, test harness, and measuring receiver—provides consistent, repeatable results across labs and vehicle types. The frequency range and emissions limits cover both passenger and commercial vehicles. 

CISPR 25 also streamlines data analysis and reporting for certification, with flexibility to support emerging technologies like electric vehicles and advanced infotainment systems. Adopting this standard helps manufacturers accelerate development, ensure compliance, and deliver reliable performance in complex EMC environments. 

How to Conduct CISPR 25 Radiated Emissions Testing 

Pre-Testing Preparation 

• Review the CISPR 25:2021 Edition 5.0 standard and determine the appropriate performance class for the product. 

• Select the measurement method: ALSE, TEM Cell, or Strip line (ALSE is the primary method for Section 6.5). 

• Prepare the test setup, including: 

• Absorber-lined shielded enclosure (ALSE) with verified absorber performance 

• Ground plane CISPR 25 compliant (minimum width 1000 mm) 

• Measuring receiver CISPR 25 compliant (spectrum analyzer or EMI receiver) 

• Appropriate antenna (log-periodic, biconical, monopole) for the frequency range 

• Test harness configuration per CISPR 25 requirements 

Testing Procedures 

• Position the EUT and test harness on the ground plane, ensuring the correct orientation for radiated emissions testing. 

• Place the antenna at the specified distance from the EUT and connect it to the measuring receiver. 

• Sweep the frequency range (150 kHz to 2.5 GHz) and record emissions using peak, quasi-peak, and average detectors as specified. 

• Compare measured emissions to the standard’s radiated emissions limits for automotive components and document all test conditions. 

Testing Report 

• Include detailed diagrams of the test setup, including ALSE, ground plane, test harness, and antenna positions. 

• Record all emissions data, frequency ranges, and detector types used. 

• Summarize compliance with CISPR 25 radiated emissions limits and performance class. 

• Provide calibration records, measurement uncertainty considerations, and any deviations from the standard procedure. 

Industry Applications and Relevance 

CISPR 25 is critical for ensuring EMC compliance and emissions validation across automotive components and systems. It is widely used to test passenger cars, commercial vehicles, electric vehicles, infotainment systems, sensors, and supply lines. 

With detailed test setups, a defined frequency range, and clear emissions limits, the standard offers a reliable framework for identifying and controlling emissions. CISPR 25 supports regulatory compliance and continuous improvement, making it essential for automotive engineers and manufacturers. 

Applus+ Laboratories: Global Expertise in Compliance Testing

Now part of Applus+ Laboratories, Applus+ Keystone delivers testing and certification services with the support of a global lab network. From innovation to market approval, we ensure your path to compliance is smooth and effective.

Contact us if you’re interested in receiving a quote or learning more about how Applus+ Laboratories can assist with your testing and certification requirements.

For more information on CISPR electromagnetic compatibility certification testing, please visit the links below.

• • CISPR 11 EMC Radio Frequency Testing of Industrial, Scientific and Medical Equipment
  • CISPR 12 EMC Testing of Vehicles, Boats, and Internal Combustion Engines
  • CISPR 14 EMC Testing of Family Appliances
  • CISPR 16 EMC Radiated Immunity and Radio Disturbance Testing
  • CISPR 22 EMC Radio Disturbance Testing of Information Technology Equipment
  • CISPR 24 EMC Immunity Testing of Immunity Characteristics
  • CISPR 25 RF Conducted Emissions
  • CISPR 25 RF Radiated Emissions
  • CISPR 32 EMC Emission Testing of Multimedia Equipment
  • CISPR 35 EMC Immunity Testing of Multimedia Equipment