JC/T 2499-2018 in English

Standard Background and Technological Evolution

With the widespread adoption of 5G communications and electronic devices, the electromagnetic wave absorption performance of building materials is becoming increasingly important. As my country's first dedicated testing standard for building material absorption, JC/T 2499-2018 fills a gap in the industry. This standard integrates advanced testing technologies such as vector network analyzers and references international standards such as IEEE 1128, forming a comprehensive testing system covering 1 GHz to 40 GHz.

Comparison of Core Test Methods

Analysis of key technical points

1. Bow method operation specifications

The test system must ensure that the center of the sample coincides with the center of the bow frame, and the background reflectivity ≤-40dB. The standard plate is made of 0.5mm aluminum, and its dimensions are selected based on the frequency: 1-4GHz: 500mm 4-12GHz: 300mm 12-40GHz: 180mm 2. Impedance Matching for the Waveguide Method According to Appendix A, the waveguide cross-sectional width (a) must meet the following requirements: a ≥ 2λ (λ is the wavelength). For 600MHz testing, the recommended dimensions are 1m × 0.5m. An extended waveguide structure is required to reduce mode interference. 3. High-Order Mode Suppression for the Coaxial Method Appendix B indicates that a square coaxial cable with a 1200mm × 1200mm outer conductor will exhibit a TE31 mode at 380MHz, requiring the use of time-domain gating technology to eliminate interference. The length of the uniform cross-section section should be ≥10m to ensure accuracy in the 30-600MHz frequency band.

Implementation Recommendations