Characteristic Analysis and Applications of Electromagnetic Shielding Materials for Wireless Communications Device

Abstract

As the trend of consumer electronics and mobile communications devices is obviously developing toward to miniature and high-speed processing, the problem involving with electromagnetic compatibility (EMC) or radio frequency interference (RFI) is becoming more critical for the system integration of high-speed digital and RF mixed signal platforms. This paper is mainly focusing on the characteristics analysis of various electromagnetic shielding materials by utilizing the various shielding effectiveness (SE) measuring methods developed by TDK and ASTM (ASTM D4935). We also adopt the electromagnetic interference (EMI) testing methods developed by IEC for chip level (IEC 61967-3 and IEC 61967-6) to investigate the characteristics and distribution of EMI noise sources. To effectively shield the electric, magnetic, or electromagnetic field originated from noise source, we thus analyze the shielding capability for various materials with different measuring methods. Finally, we will show the EMI reduction and RF performance improvement with implementation of shielding material on module under investigated. With the systematic measurement and analysis described in this paper, we can further identify the related EMI problem and resolve the severe chip or module level EMC problem more effectively.

Experimental Verification of the Shielding Properties of Selected Textile Materials in the X Frequency Band

“…Only for PPy-modified Mxene sheets coated on PET fabrics, a higher EMI shielding effectiveness of approximately 90 dB was found in a previous study [14], thus applying a much more complicated method to reach a high conductivity, as compared to using simple metallized, commercially available woven fabrics. The other SE values presented in the literature are significantly smaller, such as MXene-coated fabrics [31,32], different copper-or nickel-coated fabrics [33,34], carbon nanotube/graphene coatings [35], or coatings with conductive polymers [36,37]. Thus, our investigations show the great potential of some readily available metalized fabrics for shielding purposes.…”

“…The measurements of scattering parameters were performed using the waveguide variant of the transmission/reflection method [31][32][33][34] by means of the test set shown in Figure 2. The test set consists of two sections (W) of the WR-90 waveguide that are both 250 mm in length and two broadband SMA/WR-90 transitions (T).…”