Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
SAE J1113-21 Cancelled: Transitioning to ISO 11452-2 for Automotive Component Radiated Immunity Testing
SAE J1113-21 was a standard for electromagnetic compatibility measurement of vehicle components, specifically for immunity to electromagnetic fields from 30 MHz to 18 GHz in an absorber-lined shielded enclosure (ALSE). In 2013, SAE cancelled this standard because it became technically identical to the international standard ISO 11452-2. This article explains the background, technical requirements, and implications for engineers.
🛠️ Overview of SAE J1113-21: Radiated Immunity from 30 MHz to 18 GHz
Originally issued in 1994, SAE J1113-21 specified a test method for evaluating the immunity of vehicle components to radiated electromagnetic fields using an absorber-lined shielded enclosure. The frequency range covers VHF, UHF, and microwave bands. The standard emphasizes creating a uniform field over the test area and includes calibration procedures to ensure accuracy.
| Parameter | Requirement |
|---|---|
| Frequency range | 30 MHz to 18 GHz |
| Test environment | Absorber-lined shielded enclosure (ALSE) |
| Field uniformity | 75% of points within 0 to +6 dB of nominal |
| Calibration method | Replace EUT with field probe; power adjusted for target field strength |
| Antenna types | Biconical, log-periodic, horn, etc., depending on frequency |
| EUT positioning | On a non-conductive table; wiring harnesses routed per standard |
Note: The technical content of SAE J1113-21 became identical to ISO 11452-2 after the 2012 revision of the ISO standard. SAE cancelled J1113-21 in May 2013 to avoid duplication and encourage global harmonization.
🔍 Reasons for Cancellation and Transition to ISO 11452-2
At the August 16, 2012 SAE EMC Standards Committee meeting, the committee recommended cancellation of SAE J1113-21 in favor of using ISO 11452-2. The rationale is that after the latest revision of ISO 11452-2, the two documents were technically identical. Maintaining a separate SAE standard no longer adds value and could cause confusion in the global automotive industry.
Engineers who previously referenced SAE J1113-21 should now use ISO 11452-2. The transition is straightforward as the test setup, procedures, and acceptance criteria remain the same.
⚙️ Engineering Design Insights for ALSE Testing
Key considerations for successful radiated immunity testing in an absorber-lined chamber include:
- Field uniformity: Calibrate the field before testing by mapping the field over the test volume. Use multiple probe positions to ensure the field meets requirements.
- Absorber performance: Choose absorbers effective across the entire frequency range. Low frequencies may require longer or higher-performance absorbers to minimize reflections.
- EUT cabling: Cable routing and termination can significantly affect results. Follow the standard’s guidelines for harness placement and loading.
- Measurement uncertainty: Account for uncertainties from the field generation, measuring instruments, and setup. The standard provides guidance on acceptable levels.
⚠️ Common Mistake: Inadequate field calibration is one of the most frequent mistakes. Always replace the EUT with a calibrated field probe and verify the field before beginning tests.
Frequently Asked Questions
Why was SAE J1113-21 cancelled?
SAE J1113-21 was cancelled because its content became technically identical to ISO 11452-2. To promote global standardization and avoid maintaining duplicate documents, SAE recommended cancellation.
What standard should I use now for radiated immunity testing of vehicle components?
Use ISO 11452-2:2012 (or its latest revision) for absorber-lined chamber testing from 30 MHz to 18 GHz. It provides the same test method as SAE J1113-21.
What are the major differences between SAE J1113-21 and ISO 11452-2?
There are no technical differences. SAE J1113-21 was identical in content to ISO 11452-2 at the time of cancellation. The only differences were formatting and administrative elements.
What are the critical setup parameters for ALSE testing?
Critical parameters include field uniformity, absorber loading, antenna selection, and EUT configuration. Proper calibration and documentation are essential for repeatable results.
