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FITNESS is addressing 5 main technological challenges, to reach its ultimate objective: implement far-field communication and near-field sensing in a single technology”.

Creating conformal and even flexible metasurfaces: Direct design techniques developed for flat structures will be extended toward the control of surface waves propagating along curved objects.

Sensing of nearby objects through correlation of signals transmitted and received by all pairs of ports: Holistic approach embedding integrated electronics, with Re-Distribution Layer, with existing chips.

Lowering cost and increasing flexibility of the metaskin: enabled by usage of a limited number of sparsely distributed electronics, with spacings much larger than half wavelength (contrary to traditional phased arrays) and scanning of a high-directivity beam without creation of grating lobes.

Stepping from near-field to far-field sensor: consider the little metallic inclusions in the form of an impedance sheet to monitor leaky and surface waves, as a follow up of detailed studies of Green’s function (field distributions for a point-like current) for curved surfaces.

Synthesizing new microwave materials: low-loss, flexible and stretchable dielectrics, using expertise in the design of block copolymer structures.

FITNESS ambition is to bring the technologies at stakes from “experimental proof of concepts” to “technologies validated in lab” at the end of the project

The enabling technology:
Metasurfaces (MTS)

Thanks to the advent of ‘metasurfaces’ these near field sensing and far field communication functionalities are possible at microwave frequencies. Metasurfaces look like a printed-circuit board; they have a ground plane, a thin dielectric layer (yellow in Figure below) and, printed on top of it, a large number of subwavelength metallic patches (orange dashed), which can be modelled as a surface reactance or an impedance sheet.

A pin-feed excites an electromagnetic surface wave (SW). The SW becomes a leaky wave (LW) when a modulation appears in the shape and orientation of the electrically small patches.

FITNESS will develop a “smart skin” that will produce a kind of “electromagnetic aura” around a robot or human body (region of “reactive fields”). Energy levels are safe, since they are about hundred times lower than those radiated by a cell phone.

Left: meta-skin with a few feeds (thin red segments), with transmit and receive ports (bottom blue and red arrows); the signal is conveyed through surface waves (SW) and leaky waves (LW). Right: same phenomena, perturbed by a non-contact touch (scattering by hand), leading to different transmittances (smaller red arrows).

Integrated Electronics :

FITNESS proposes a near-field to far-field sensor, based on surface waves (SWs) and their possible transformation into leaky waves, to be wrapped around robots or humans.

The measurement of the correlation between transmitted and received signals at all pairs of ports will also be used to monitor the effects of folding the flexible skin.

The control of surface waves clearly differentiates the proposed technology from near-field radar.

Conformal electronics ( © CNRS)

Microwave materials:

Advances regarding microwave materials are lagging behind, curtailing the development in the field. The integration of mechanical properties (i.e., elastic deformation, self-healing) in low-loss materials is a challenge.

FITNESS includes important innovations toward thin integrated electronics distributed along the MTS, by designing and developing low-power SOI receiver chips, integrating power dividers, mixers and low noise amplifier (LNA) modules for the monitoring of received signals at each port.

Nearfield to far field sensors:

In FITNESS, new multifunctional polymer substrates and compatible metallization techniques for MTSs and electronics will be developed to achieve low losses and advanced mechanical functions, e.g. structures that are flexible, stretchable, or even self-heal.