Electromagnetic compatibility - radiation emission test construction layout analysis

1.Overview of Radiation Emission (RE) Tests:

In electromagnetic compatibility testing, the radiated emission test measures the strong radiated disturbance field that EUT propagates through space. It can be divided into magnetic field radiation and electric field radiation. The former is used for lamps and induction cookers, while the latter is widely used. In addition, household appliances and power tools, as well as auxiliary equipment for AV products, require active radiation emissions (referred to as disturbance power).

2. Radiation Emission (RE) Test Standard:

a) Magnetic field radiation: CISPR15 (lamps with operating current frequency exceeding 100Hz), CISPR11 (induction cooker);

b) Disturbance power: CISPR14-1 (except for some equipment with a working frequency not exceeding 9kHz), CISPR13 (only for auxiliary equipment).

c) Electric field radiation: CISPR22/EN5022 (information technology products), CISPR13/EN5013 (audio products), CISPR11/EN5011 (engineering medicine), CISPR14-1, CISPR15/EN5015 (lamps);

3. Radiation emission (RE) test method:

Radiation emission testing instruments and equipment:

a) Magnetic field radiation: receiver. Triple loop antenna or single small loop far antenna;

c) Electric field radiation: receiver (below 1G), spectrometer (above 1G), anechoic chamber, antenna (below 1G), generally double.

b) Disturbance power: receiver. Power absorption clamp. Combination of cone and logarithmic period or broadband composite antenna, horn antenna above 1G);

The receiver complies with the requirements of CISPR16-1-1, antenna. The site complies with the requirements of CISPR16-1-4, and the absorption forceps comply with the requirements of CISPR16-1-3.

4. Radiation emission (RE) test SETUP:

Figure 1 shows the layout of radiation emission tests in accordance with standards such as CISPR16.CISPR11.CISPR13.CISPR15.CISPR22 and EN5022.

Figure 1. Layout of Radiation Emission Test

The layout of desktop equipment under test is shown in Figure 2, and the specific requirements are as follows:

(1) The I/O cable connected to the ground shall not be less than 40cm;

(2) In addition to the actual load connection, the device under test can also be connected to analog loads, but the analog loads should conform to the impedance relationship and represent the actual situation of the product application;

(3) The power cord of the equipment under test and auxiliary equipment AE shall be directly inserted into the ground socket, and the socket shall not be extended;

(4) If the test equipment itself has more cables, they should be carefully straightened out, processed separately, and recorded in the test report to obtain a reproduction of the retest;

(5) The distance between the tested equipment and the auxiliary equipment AE is 10 cm;

The layout of the vertical equipment under test is shown in Figure 3, and the specific requirements are as follows:

(1) The I/O interconnects between cabinets should be placed naturally. If they are too long, they must be bundled as a 30-40cm wire harness;

(2) The equipment under test is arranged on a metal plane with an insulation interval of about 10cm from the metal plane; Cables connecting simulated loads or external ports in a dark room should pay attention to the insulation of the same metal plane;

(3) If the power cord of the equipment under test is too long, a harness with a length of 30-40cm should be bundled or shortened sufficiently;

(4) If the test equipment itself has more cables, they should be carefully straightened out, handled separately, and recorded in the test report to obtain repeatability for the retest.

In electromagnetic compatibility, the layout of radiation emission tests and radiation emission tests for automotive electronic equipment required by the CISPR25 standard is shown in Figure 4. In the radiation emission test, automotive electronics are measured and placed in a semi anechoic chamber, with the receiving antenna 1m away from the EUT harness. When the receiving antenna is vertically polarized and horizontally polarized, the maximum radiation point radiation signal is transmitted through a cable to the outside of the semi anechoic chamber.

Figure 4. Layout of radiation emission test required by CISPR25 standard