Digital Fabrication of Frequency Selective Surfaces for In-Building Applications Using Inkjet Printing Technology

This thesis presents work on the inkjet printing manufacture of frequency selective surfaces intended for in-building applications using silver nanoparticle inks. The aim of this research is to investigate the performance of inkjet printed FSS panels in terms of transmission response, element conductivity, and the resolution of the printed lines, all of which are produced efficiently in terms of cost and resource usage. Different FSS design were investigated from simple elements such as linear dipoles, square loops and convoluted square loop elements.

Various techniques were used in the manufacturing process such as different ink drop spacing, number of jetted ink layers, and different sintering methods, with the aim of achieving low cost manufacturing with a reduced amount of deposited silver inks and sintering time and temperature. Additionally, further reductions in the deposited ink were considered by the introduction of frame elements.

The research also focuses on factors that could affect the transmittivity/reflectivity of the FSS screen, such as the influence of imperfections in the printed elements. The imperfections are expected in the case of low cost mass production, therefore it is important to understand to what extent they could be tolerated whilst still providing adequate performance.

Finally, the work also considers developing novel slotted FSS arrays operating at low frequency bands such as the TETRA emergency band and suitable for additive manufacturing.