Research on EMC evaluation technology for vehicle Ethernet devices

Research and standardization activities on EMC measurement methods of
EMC countermeasure devices for automotive networks

Focus on common mode chokes and ESD suppression devices used for 100BASE-T1, 1000BASE-T1, 10BASE-T1S, etc.
・Optimize EMC test boards
・Clarify calibration methods and requirements for ensuring
　measurement accuracy
・Contribute to improving test reliability

Research and standardization activities on measurement method of ESD damage test for EMC countermeasure devices

・Optimized ESD damage test boards
・Investigate the possibility of replacing ESD gun with
　TLP-HMM (Transmission Line Pulse – Human Metal Model)
・Contribute to improving test reliability

Research and standardization activities on measurement method of ESD saturation test using TLP

・Clarify test parameters and propose new calibration methods ・Contribute to improving test reliability

Research of effect of powered ESD on communication quality of automotive
Ethernet IC

・Elucidate noise characteristics superimposed on
　differential communication system by mode conversion
・Elucidate mechanism that causes communication errors
・Develop a simulator that can quantitatively analyze
　communication performances under noise environments

Research on EMC test setup including wire harnesses

・Analyze coupling and propagation between common mode
　and differential mode noises due to wire harness layout and
　EUT installation conditions

【Evaluation example】
To analyze the behavior of noise arriving at a differential communication system, it is necessary to consider the common-mode coupling and propagation of the noise to the differential line and the mode conversion at the termination structure. Since the amount of the mode conversion at the termination depends on the grounding condition of the electronic equipment, the board wiring,
and mounted components. Therefore, a method that can measure the mode conversion including the entire termination is required.
This paper1）proposes two methods to extract the electrical characteristics of the termination structure by measuring three port S-parameters using a current probe. The validity of the methods was experimentally verified. 　　　　　　

1) M. Yoshida, Y. Yano, J. Wang, and T. Ishida, “Measurement Method for Mode Conversion of Differential Communication Line Termination Structures (in Japanese),” IEICE Transactions on Communications , Vol.J105-B, No.12, pp.928-937, Dec. 2022. DOI: 10.14923/transcomj.2022JBP3020. 　

EMC-related test items that can be performed in the test house

The EMC team of NITech conducts tests, provides test data and consulting from a preliminary test perspective on the following test items, while closely exchanging information with FTZ of Germany.
・IEC 62228-5 Annex E Characterization of Common Mode Chokes for EMC Evaluation of Ethernet Transceivers、
・Open Alliance - IEEE 100BASE-T1/1000BASE-T1 EMC Test Specification for Common Mode Chokes Ver. 2.0、
・（Now voting）The following items in IEEE 10BASE-T1/1000BASE-T1S EMC Test Specification for Common Mode Chokes：
- Mixed-mode S-parameter measurement
- ESD damage test
- Saturation test at ESD
・IEC 62228-5 Annex F Characterization of ESD Suppression Devices for EMC Evaluation of Ethernet Transceivers、
・Open Alliance - IEEE 100BASE-T1/1000BASE-T1 EMC Test Specification for ESD Suppression Devices Ver. 2.0、
・（Now voting）The following items in IEEE 10BASE-T1/1000BASE-T1S EMC Test Specification for Common Mode Chokes：
- S-parameter measurement mixed mode
- ESD damage test
- ESD discharge measurement