Scope of application:Used for textiles, plastic cloth, metal sheet, non-conductive material surface coating or plating, metal mesh, conductive film,Test of electromagnetic shielding effectiveness of electromagnetic shielding materials such as conductive glass and conductive dielectric plates (flange coaxial method).

Applicable standards:GB/T 23326 Stainless steel fiber and cotton polyester blended electromagnetic wave shielding natural color cloth;GB/T 25471 Measurement Methods for Shielding Effectiveness of Electromagnetic Shielding Coatings;Measurement method of shielding effectiveness of SJ 20524 materials;ASTM 4935, etc.

Technical indicators:

A, signal source:

1. Test frequency range: 300 KHz ~ 3000 MHz;

2. Frequency stability: ≤ ± 5 × 10-6;

3. Frequency resolution: 1Hz;

4. Signal purity: ≤-65dBc/Hz (partial 10 KHz);

5. Output level:-45dBm ~ 10 dBm;

6. Level accuracy: ≤ ± 1.5dB(25 ℃ ± 5 ℃,-45dBm ~ 5 dBm);

7. Harmonic suppression ratio: ≥ 30dB(1MHz ~ 3000MHz),≥ 25dB(300KHz ~ 1MHz);

8. Directivity: ≥ 50dB (after vector calibration);

9. Power scanning:-8dBm ~ 5dBm;

10. System impedance: 50 ohms;

B, receiver:

1. Frequency range: 300KHz ~ 3000MHz;

2. Resolution bandwidth: 100 Hz ~ 20 KHz;

3. Dynamic range: ≥ 95 dB ( RBW = 1 KHz );

4. Maximum input level: 10dBm;

5. Input damage level: 20dBm (DC 25V );

6. Port: VSWR ≤ 1.2;

C, instrument principle

Structure Diagram

1. Shielding effectiveness (SE）

 The ratio of the power or voltage received with and without shielding material at the same excitation level

Logarithmic. The formula is as follows:

VO-Receiving voltage without shielding material;

VI-Receiving voltage with shielding material;

PO-received power without shielding material;

PI-Received power with shielding material;

2. Test Process

By standardGBT25471-2010 to the requirements, after cutting test and humidity control. First, use the reference sample to measure at multiple frequency points, record the received value PO (or VO) at each frequency, and then replace the measurement sample to measure at multiple frequency points, and record the received value PI (or VI) at each frequency. The shielding effectiveness was calculated using the above formula.