Usually the basic properties of conventional dielectrics and magnetic materials are described by permittivity and permeability. There are no means for the direct measurement of electromagnetic parameters, which are dependant on the model used for their extraction. Approaches to measurements of even these fundamental electromagnetic characteristics of materials vary dramatically for electromagnetic waves of different frequencies, e.g. radio waves and light, and require specialised measurement techniques. These difficulties are dramatically escalated in electromagnetic characterisation and metrology of nanostructured materials. At the present stage of research, development and exploitation of nanoparticles and nanocomposites, they are characterised only in terms of geometrical parameters (particle size, lattice period, etc.) and sometimes by chemical reactivity. Electromagnetic characterisation of nanocomposite materials and understanding the structure-electromagnetic properties relationship, especially in the optical range, is a novel field of electromagnetic science. A comprehensive phenomenological description, with definitions and a consistent metrology of the constitutive electromagnetic parameters of nanocomposites, are paramount for their applications. Examples of nanocomposites include photonic crystals and optical metamaterials (arrays of plasmonic nanowires, carbon nanotubes, artificial optical magnetics, super- and hyper-lenses). The present lack of established, adequately tested, and widely adopted characterisation methods, tools and test procedures suitable for unambiguous description of electromagnetic properties of nanocomposites hinders further development and use of novel materials in practical applications, especially in optical devices and sensors.

The main challenges in electromagnetic characterisation and metrology of nanostructured materials include:
- Mesoscopic scale and regime of operation. In the majority of practically realizable nanostructures the nanoparticle feature sizes and the characteristic lattice constants are smaller than the operational wavelength of light but comparable with it. For example, a device can operate at the wavelength of 500-600 nm, the structural periodicity is 50-100 nm, and the particle sizes are of the order of 30-70 nm. Such structures can still be described in terms of effective parameters (permittivity and permeability) of an equivalent homogeneous medium. However, the conventional models based on quasi-static homogenisation procedures normally applied at the atomic level are not applicable here, and the resulting effective phenomenological parameters (like permittivity and permeability) have different physical meaning as compared with conventional materials.

The main problems to be addressed are:
- The complex geometry and plasmonic resonances of individual nano-inclusions, which form a composite material, cause material resonances even for electrically dense composites. The standard description using the models of a homogenised effective medium is inapplicable near these resonant frequencies.
- Realisable nanocomposite films usually contain only a few layers of nanoparticles (often just one layer). The description of layer properties in terms of bulk material parameters (permittivity and permeability) has limited validity.
- The lack of consistent phenomenological models and established system of characteristic parameters of nanostructured materials inhibit the development of coherent measurement methodologies and material metrology.
In the present situation, when approaches to electromagnetic characterisation of nanocomposites are only under initial development, researchers either avoid the use of the conventional material parameters for such structures or extend the existing standard definitions beyond the limit of their applicability thereby sometimes violating the basic physical principles of causality, passivity and other fundamental laws. Due to the very nature of the nanostructured materials, the effective electromagnetic parameters have limited application range, but these constraints are yet not well defined and even the existing knowledge is not properly disseminated. As a result, the material users in industries and SMEs often cannot adequately exploit the measured parameters of nanostructures for design of new devices. Current research work on development of electromagnetic characterisation methods and measurement techniques is very active especially in Europe, with a large part of efforts concentrated in the Virtual Institute for Artificial Electromagnetic Materials and Metamaterials, the leading beneficiaryof this proposal. Considerable coordination efforts are needed for timely solution of the current problems in electromagnetic characterization of nanomaterials, and we propose to make use of the available durable coordination infrastructure and scientific expertise of the Metamorphose VI to solve these current problems.

The main project objective is to consolidate efforts and bring coordination in the European work towards development, testing, and dissemination of methods and tools for electromagnetic characterisation and metrology of nanostructured composite materials. The main novel characterisation approaches are focused on intrinsically interrelated developments and harmonisation of the material phenomenological models, standardisation of characteristic parameters and measurement techniques for evaluating the specified parameters.

The necessary characterization techniques should be a) developed; b) tested; c) compared; d) catalogued and e) disseminated to the standardisation bodies, industries and SMEs. The proposed project aims at initiating and coordinating the cohesive actions in all the aforementioned directions.