SYMETA officially began on 1st March 2016. Our focus was to create novel, multi-functional 3D Metamaterials using emerging additive manufacturing techniques and novel materials.
We recognised that the technical challenges posed were broad:
Addressing the problems posed by 3D multi-meta-atom fabrication.
Developing a suitable range of base additive layer materials from which metamaterials can be made.
Modelling, designing and fabricating meta-atoms with metal, dielectric and magnetic inclusions and, fabricating and characterising test samples with a range of electromagnetic properties.
Fabricating metamaterials using additive manufacturing and measuring their performance.
Using additive manufacturing techniques to scale the primary components and translate them into demonstrator devices.
To deliver this our research was focused into two complementary, interlinked and dependent work streams:
Work Stream 1: Powder to Product
While additive manufacturing (AM) of polymers and metals are individually reasonably established, there have been some considerable recent research developments in the additive manufacture for ceramics, but it must be highlighted that this field is still at its very infancy. As with conventional fabrication methods, attention has only been given to technical/engineering ceramics. However electroceramics and their requirements for successful processing and printing have not been extensively researched. For example, the development of 3D printable ceramic ink formulations needs a significant understanding and control of their particle size distribution, rheological, visco-elastic and visco-plastic properties and how they can be tailored to achieve the designed printed components overcoming the major challenges of cracking, interfacial delamination and buckling.
Within this work stream commercial, novel and bespoke material (both ceramic and metal) compositions for electromagnetic devices are being prepared (SU WP2) and converted into printable ink formulations with suitable rheological characteristics (LU MAT WP4) for additive manufacturing processes of green body formation (LU AM & LU MAT WP5) followed by de-binding and sintering.
Given the multi-material nature of some of the metamaterial designs, material compatibility has been identified as a major challenge. The differences in the inherent physical properties, such as sintering temperature, of both bespoke and conventional materials that are being investigated impacts upon the final product’s overall mechanical, EM and physical properties.
Work Stream 2: Meta-atoms to Metamaterials Demonstrator
The compilation of a 'palette' of meta-atoms (the basic building blocks of metamaterials) is a key challenge when organising them systematically to ensure that a bulk metamaterial demonstrates the required electromagnetic properties.
These work streams were linked together by Loughborough University characterising both the materials and metamaterials (often a composite of multiple materials) over a range of frequencies in the GHz range such as those used for radar, 4G and 5G, V2X and satellite communications.