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Introduction of Radar Wave Immunity Test for Auto Parts

Release time:

2023-07-28 15:33

Source:

　　1 Introduction

Radar (Radar) is a kind of electromagnetic wave detection and measurement technology, is widely used in military, aviation, meteorology, navigation and other fields. The most critical component of the radar system is the radar wave.

Radar waves are electromagnetic waves at a specific frequency, usually in the frequency band between radio frequency and microwave. They propagate in space and reflect, scatter, and refract when they interact with the target or medium. By receiving and analyzing the signals returned from the target, the radar system can determine the position, distance, speed, shape and other information of the target.

The radar transmits the radar wave to detect at the same time, it also transmits the electromagnetic wave to its detection azimuth, which is also a kind of electromagnetic wave interference signal. These disturbances may result in reduced electrical function in the vehicle, or even malfunction or damage. The worst case may lead to vehicle control system or power system failure, causing traffic accidents. Therefore, the anti-interference of automobile parts to electromagnetic waves is particularly important. Radiated immunity radar wave test is an effective method to verify the anti-interference ability of key parts of vehicles.

The general radar wave test requirements are mainly reflected in the enterprise standards of automobile enterprises, and this paper expounds the test method of radar wave immunity based on the research of ISO 11452-2, Ford's electromagnetic compatibility standard Ford-FMC1278-2015 and General Motors electronic parts EMC test standard GMW3097-2015.

　　2 Radar wave immunity test test level

General Motors requirements for radar wave test level are as follows:

It can be seen from the text that the GM radar wave test frequency band is 1200MHz-1400MHz, the test level is 300 V/m, and the dwell time of level 1 and level 2 are different.

Ford's requirements for radar wave test level are as follows:

Ford's radar wave test frequency bands are 1200MHz-1400MHz and 2700MHz-3100MHz. General auto parts need to meet 300 V/m, and some components need to meet 600 V/m. For the reverberation chamber test method, the pulse dwell time needs to be 6 seconds.

　　3 Test frequency

Ford and General Motors have different test frequencies for radar wave tests. The specific test frequencies of each automobile manufacturer are as follows.

Ford's frequency requirements for radar wave tests:

General Motors radar wave test frequency requirements:

Through calculation, the frequency points that need to be tested in the radar wave band are as follows:

　　4 Arrangement of Radar Wave Test

The arrangement of radar wave test is similar to that of general radiation immunity test above 1GHz, but there are still some differences in details. And Ford and General Motors two car companies on the radar wave test arrangement has a number of different.

　　4.1 Ford Motor Company Radar Wave Test Arrangement

The height of the test table used for radar wave test is (1000±50)mm, and the height of the test table used for general radiation immunity test is (900±50)mm.

During the radar wave test, there is no need to lay a ground reference plane (copper plate) on the experimental table, while the general radiation immunity test requires laying a ground reference plane on the experimental table.

Artificial network AN is not required for power supply to DUT for radar wave test, while artificial network AN is required for general radiated immunity test.

For radar wave test, the distance between the radar wave transmitting antenna and the desktop height is (50±10)mm, while for general radiation immunity test, the distance between the transmitting antenna and the desktop height is (100±10)mm.

During the radar wave test, the DUT and cable do not need to be placed in a non-conductive medium of (50±5)mm, while the non-conductive medium is required for the general radiation immunity test.

　　4.2 General Motors Radar Test ClothSet

The height of the test table used for radar wave test is (900±100)mm, and the height of the test table used for general radiation immunity test is (900±50)mm.

For the requirements of the experimental table, the radar wave test and the general radiation immunity are the same, and the grounding reference surface (copper plate) needs to be laid on the experimental table.

Artificial network AN, radar wave test and general radiation immunity test are the same, all need to connect artificial network.

From the height of the experimental desktop, the radar wave test is the same as the general radiation immunity test, and the distance between the radar wave transmitting antenna and the desktop height is (100±10)mm.

For non-conductive medium, the radar wave test is the same as the general radiation immunity test. Both DUT and cable need to be placed in (50±5)mm non-conductive medium.

　　5 Field strength calibration

　　5.1 signal source output

Ford and General Motors radar test requirements are the same, continuous wave CW for field strength calibration, Pulse modulated for testing.

　　Radar Wave Calibration Method for Ford Motor Company of 5.2

There are three methods for radar wave test calibration of Ford Motor Company: CW E-Field Probe calibration method, Pulsed E-Field Probe calibration method and antenna calibration method. The calibration requirements for the three methods are as follows.

  • CW E-Field Probe Calibration Method

There are two commonly used field strength probes for this calibration method.

For Type A, the field strength probe is placed on a non-conductive test table with a height of 1000mm, and the phase center of the probe is 125mm above the test table. The front section of the radar wave antenna is 1000mm away from the phase center of the probe, and the center is 1050mm away from the ground.

For vertical and horizontal polarization calibration, read the value of the specific axis of the field strength probe, not the vector composite value. The vertical polarization of the antenna corresponds to the Z-axis alignment of the field strength probe, and the horizontal polarization corresponds to the X-axis alignment of the field strength probe.

The forward peak power is used as the calibration reference, and the field strength calibration uses CW, which does not allow calibration of low-level tests and references to high-level tests.

The calibration of the field strength probe includes two specific frequencies, 1.3GHz and 2.9GHz.

For type B, the placement height of the field strength probe and the distance requirements of the radar wave antenna are the same as those of type A. It should be noted that the handle of the probe must be inclined 35 degrees upward relative to the surface of the test table and 135 degrees relative to the X axis of the test table.

For vertical and horizontal polarization calibration, read the value of the specific axis of the field strength probe, not the vector composite value. The vertical polarization of the antenna corresponds to the Z-axis alignment of the field strength probe, and the horizontal polarization corresponds to the X-axis alignment of the field strength probe.

The forward peak power is used as the calibration reference, and the field strength calibration uses CW, which does not allow calibration of low-level tests and references to high-level tests.

The calibration of the field strength probe includes two specific frequencies, 1.3GHz and 2.9GHz.

  • Pulsed E-Field Probe Calibration Method

The direct use of the pulse field strength probe calibration method requires Ford EMC approval. The field strength probe needs to meet the requirements of CW E-Field Probe, but CW measurement is not required. Currently, the only approved probe is PL 7004.

  • calibration method of receiving antenna

The following figure is a schematic diagram of the receiving antenna calibration arrangement. This method can use continuous wave (CW) or pulsed power amplifiers. Typical receiving antennas include, but are not limited:

A,ETS Linux: DRG 3115

　　B，Antenna Research：DRG118/A

C,Rohde & Black: HF906

The phase center of the antenna is located 125mm above the actual test reference ground plane. The forward peak power is used as the calibration reference, and it is not allowed to calibrate low-level tests and refer to high-level tests.

　　5.3 General Motors Corporation Radar Wave Calibration Method

There are two methods for General Motors radar wave test calibration: CW E-Field Probe calibration method and antenna calibration method. The calibration requirements for both methods are as follows.

  • CW E-Field Probe Calibration Method

There are two commonly used field strength probes for this calibration method.

For Type A, place the field strength probe on a test table with a height of 900mm, and the phase center of the probe is 125mm above the ground reference plane of the test table. The probe phase center records the edge of the table 100mm. The front section of the radar wave antenna is 1000mm away from the phase center of the probe, and the center of the antenna is 1050mm away from the ground.

For vertical and horizontal polarization calibration, read the value of the specific axis of the field strength probe, not the vector composite value. The vertical polarization of the antenna corresponds to the Z-axis alignment of the field strength probe, and the horizontal polarization corresponds to the X-axis alignment of the field strength probe.

The forward peak RMS power is used as the calibration reference, CW is used for field strength calibration, and the calibration level is 300 V/m.

The calibration frequency of the field strength probe shall contain at least 1.3GHz frequency points.

For type B, the placement height of the field strength probe and the distance requirements of the radar wave antenna are the same as those of type A. It should be noted that the handle of the probe must be inclined 35 degrees upward relative to the surface of the test table and 135 degrees relative to the X axis of the test table.

For vertical and horizontal polarization calibration, read the value of the specific axis of the field strength probe, not the vector composite value. The vertical polarization of the antenna corresponds to the Z-axis alignment of the field strength probe, and the horizontal polarization corresponds to the X-axis alignment of the field strength probe.

  • calibration method of receiving antenna

The following figure is a schematic diagram of the receiving antenna calibration arrangement. This method can use continuous wave (CW) or pulsed power amplifiers. Typical receiving antennas include, but are not limited:

A,ETS Linux: DRG 3115

　　B，Antenna Research：DRG118/A

C,Rohde & Black: HF906

The phase center of the antenna is located 150mm above the actual test reference ground plane. Calibrated and actual tested peak RMS forward power with a calibration level of 300 V/m.

　　6 Conclusion

With the wide application of radar technology in different fields, the electromagnetic interference problem will become more complex, and the electromagnetic wave resistance of automobiles will become more and more complex and strict.

In short, the radar wave test of auto parts is an important work that can help automakers and suppliers ensure that their products meet quality standards and provide a safer and more reliable driving experience.

Century Wisdom (Suzhou) Testing Technology Co., Ltd

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