Hui Chao Zhao

The Thinning Study of λ/4 Type Absorber Made of Carbon Fiber Membrane and Gypsum Board

large thickness of λ/4 type absorber has been an important issue, which affects its application and urges to address. In this paper, λ/4 Type absorber made of carbon fiber membrane, instead of resistive film, and Gypsum board. Its designed for thinning and we took Simulation analysis and experimental testing for it. Results show that, while carbon fiber membrane with a length of 2mm and content of 2.8%, λ/4 type gypsum composite absorber has better absorbing in S-band. Compared with the resistive film, absorber achieved thinning of 10.6%.

The Design and Preparation of X Band Absorbing Insulation Coatings

According to the principle of electromagnetic wave absorption, functionally reforming thermal insulating materials for building, through designing and theoretically simulating of the λ/4 model, using carbon fiber film, the article has successfully prepared insulation coatings for X-band electromagnetic wave absorption. Result shows, with the thickness of 3.0 mm in 8 ~ 12 GHz band, 100% of bandwidth below-10 dB can be reached. New materials can be used such as the surface of the thermal insulation of buildings and X-band electromagnetic interference protection.

The Design and Preparation of Composite Gypsum Boards Absorber Based on Phase Modulation Membrane

According to the principle of electromagnetic wave absorption, functionally reforming thermal insulating materials for building, through designing and theoretically simulating of the λ/4 model, the article has successfully prepared EPS composite gypsum boards for electromagnetic wave absorption. The result shows that, a maximum absorption of-18.7dB at 3GHz and 85% of bandwidth below-10dB was achieved under following conditions: using 380Ω/□ resistive film, specimen thickness of 1.50cm. However, by using phase modulation membrane (PMM),it achieved a maximum absorption of-20dB and 100% of bandwidth below-10dB. This new composite materials can be used for electromagnetic interference protection for WLAN and indoor electromagnetic radiation pollution control.

The Impact of λ/4 Type Absorber Protective Layer 's Thickness on Absorbing Properties

Abstract .Electromagnetic radiation affects normal operation of electronic devices and causes harm to human health, the use of electromagnetic radiation protective material, especially the electromagnetic wave absorption material, is an effective method for interference control and radiation protection, λ / 4 type dielectric absorber with a simple and practical nature, the protective layer should be added to ensure its durability in practice, this article discusses the gypsum board as the substrate, the thickness of conventional protective layers material impacts on the absorbing properties. Studies show that: the position of absorption peak moves to lower frequency with increase of the protective layers thickness by the theory and experiment, this paper puts forward the protective layers thickness criterions impact on the absorption characteristics, the thickness less than 0.05 cm has little effect on absorption characteristics in S band , which can simplify theoretical calculation and be convenient to select a material; when the thickness of the protective layer has a significant effect on absorption, the relationship among the parameters of absorber can be found according to theoretical simulation, thereby reducing or eliminating the impact of protective layer thickness on absorption characteristics.

Broadening Design and Preparation of MDF Absorber for Electromagnetic Pollution Control in S-Band

This paper reported a new type MDF absorber of high absorption and Broadband was successfully prepared, according to the Electromagnetic Wave Absorbing Theory, by means of the theoretical design and simulation analysis by using MDF as the dielectric material and And with the resistance film composite. Results shown that the resistance of resistive film was 195Ω/□, the monolayer combined sample with thickness as 1.4cm in 2~4 GHz frequency bands, the range of absorbing over -20dB could achieve 50%, and all absorption could exceed -15dB in the whole S-band, the maximum absorption peak was -25dB, moreover, the absorption bandwidth of MDF was more than λ/4 Type EWM-absorber. The new materials could be used to improve residential electromagnetic environment and control pollution.

The Double-Layer Matching Design of Broad-Band Foam Cement Absorbing Panel for Electromagnetic Pollution Control

Based on the principle of electromagnetic wave absorption, through the double-layer matching design and simulation analysis, taking foam cement panel as the dielectric material, combining with the resistive film, the paper has successfully prepared high-performance and broad-band foam cement absorbing panel for electromagnetic pollution control. The result shows, with the use of double-matching design that combines 140 Ω/□ resistive film with foam cement absorbing panel whose each layer thickness is 1.4 cm, in the S band , 100% of bandwidth below-10 dB and 95% of bandwidth below-14 dB can be reached, a maximum absorption of-19.6 dB at 2.45 GHz, the width of the absorption is far more than that of λ/4 type absorber. New materials can be used for the improvement of indoor electromagnetic environment and pollution control.

The Design and Preparation of Foam Concrete Absorber for WLAN Anti-Jamming EMW-Absorber

This paper reports that according to the principle of EMW-absorption, thermal insulating EMW-absorber for building was designed and theoretically simulated of the λ/4 type. The EMW-absorption properties of composites in the band of 2-4 GHz were examined, A maximum absorption of-20 dB at 3 GHz and 80% of bandwidth below-10 dB was achieved under following conditions: using 380Ω/□ resistive film, specimen thickness of 2 cm. Similarly, absorbing materials for 2.45 GHz have successfully designed and prepared,a maximum absorption of-17 dB at 2.45 GHz, and 65% of bandwidth below-10 dB can be reached. New materials can be used for electromagnetic interference protection for WLAN and indoor electromagnetic radiation pollution control.