Fabrication and evaluation of solid freeformed electromagnetic bandgap structures

Lu, Xuesong, Lee, Yoonjae, Yang, Shoufeng, Hao, Yang, Evans, Julian R.G. and Parini, Clive G. (2009) Fabrication and evaluation of solid freeformed electromagnetic bandgap structures. Journal of Physics D: Applied Physics, 42 (14), 145107. (doi:10.1088/0022-3727/42/14/145107).

Abstract

Microwave electromagnetic bandgap (EBG) structures have potential applications in improving the radiating features of antennas and the transmission properties of waveguides. Extrusion freeforming is a rapid prototyping technique for assembling ceramic dielectric lattice structures directly from a computer design file. It is without heating, cooling or polymerization processes to contend with at the construction stage. Various limitations on overall build thickness prompted us to explore lamination by welding to produce larger three-dimensional quasi-crystals. Microwave transmission through normal and side incidence showed that the bandgap frequency was in the 90–110 GHz region in all directions, matching the design that was informed by computer modelling. In order to image the EBG internal crystal structure, micro-computed tomography was used for scanning and reconstruction. Finally, the effect of structural defects including roundness and sagging of filaments and deviation of inter-filament spacing caused by fabrication errors on bandgap frequency was investigated.

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Contributors

Author: Shoufeng Yang

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