Calculation of the Shielding Effectiveness of Carbon-Fiber Composite Structures

• Main Author: Ansarizadeh, Mohammadali
• Format: Others
• Published: 2013
• Online Access: http://spectrum.library.concordia.ca/977705/1/Ansarizadeh_MASc_F2013.pdf; Ansarizadeh, Mohammadali <http://spectrum.library.concordia.ca/view/creators/Ansarizadeh=3AMohammadali=3A=3A.html> (2013) Calculation of the Shielding Effectiveness of Carbon-Fiber Composite Structures. Masters thesis, Concordia University.

Carbon-fiber composite (CFC) materials are replacing metals in the construction of modern aircraft because of their outstanding strength/weight ratio. The purpose of this thesis is to identify the capabilities and limitations of the commercially available software in calculating the shielding effectiveness (SE) of CFC structures. This work is started by a literature survey focused on the characterization and modeling of CFC panels. The homogenized model of CFC panels is analyzed using the skin-effect approximation in a method of moments (MoM) solution. It is found that the stack-to-sheet conversion is a limiting factor in the skin effect approximation and not the homogenization scheme. Experimental results are presented which indicate that performance of monopole antennas up to a frequency of 12.5 GHz is not altered by replacing a metallic ground plane with a CFC one. Also, a monopole antenna is mounted on hollow CFC and aluminum cubes with the same physical dimensions and the radiated electromagnetic interference (EMI) inside the cube are theoretically compared. Although wire meshes with unbonded junctions are better shields it is shown that this is less important for meshes is epoxy as compared to free space. For CFC materials reinforced with woven carbon-fiber fabrics the effects of physical contact between orthogonally oriented fiber bundles are examined. It is found that bonding CFC fiber bundles at the junctions actually improves the shielding performance. The simulation results for the electric and magnetic SE inside a hollow spherical CFC shell are compared with the benchmark analytic solutions. It is shown that the analytic solutions could not be numerically evaluated unless the wave functions are expressed in terms of the thickness of CFC materials.