Centre National De La Recherche Scientifique

Time Reversal Communications

Université Paris 7—denis Diderot

Centre National De La Recherche (cnrs)

Université Paris Diderot-paris 7

Centre National De La Recherche Scientifique-cnrs

Avantix

Arnaud Tourin

Mathias Fink

Geoffroy Lerosey

Julien De Rosny

Fabrice Lemoult

Julien De La Gorgue De Rosny

Arnaud Derode

Matthieu Dupre

Christian Leray

The invention relates to a method and a device for generating high-power electromagnetic radiation. A transmission antenna of a transmission device capable of emitting an electromagnetic transmission wave is arranged in a reverberation cavity comprising openings. The method includes determining an electromagnetic temporal waveform F focused in a desired direction of focus outside the cavity; and emitting an electromagnetic transmission wave E having temporal waveform F into the cavity using the transmission device.

Method for generating high-power electromagnetic radiation

A device () for receiving and/or emitting an electromagnetic wave, comprising a medium () of dielectric material, a plurality of passive resonant elements () incorporated inside said medium, the plurality of passive resonant elements () comprising a frequency band-gap, two neighbor passive resonant elements belonging to the plurality being spaced apart from each other of a first distance lower than &#x3bb;/4, and at least one active resonant element () incorporated inside said plurality, said active resonant element () having a second structure different from a first structure of the passive resonant elements (), so that said active resonant element () has at least a second resonance frequency comprised inside the frequency band-gap of said plurality of passive elements ().

Device for receiving and/or emitting a wave, a system comprising the device, and use of such device

A device for receiving and/or emitting an electromagnetic wave having a free space wavelength &#x3bb;comprised between 1 mm and 10 cm, comprising a medium () of solid dielectric material and the free space wavelength &#x3bb;corresponding to a wavelength &#x3bb; inside the medium, a plurality of conductor elements () incorporated inside the medium and spaced apart from each other of a distance lower than &#x3bb;/10, and one antenna element (). The conductor elements form small loop elements. A tuned conductor element among the conductor elements has a first end at a distance from the antenna element which is lower than &#x3bb;/10, and has an electric resonance frequency corresponding to the wavelength &#x3bb;.

Device for receiving and/or emitting an electromagnetic wave, system comprising said device, and use of such device

A device for receiving and/or emitting an electromagnetic wave having a free space wavelength &#x3bb;comprised between 1 mm and 10 cm, comprising a medium () of solid dielectric material and the free space wavelength &#x3bb;corresponding to a wavelength &#x3bb; inside the medium, a plurality of conductor elements () incorporated inside the medium and spaced apart from each other of a distance lower than &#x3bb;/10, and one antenna element (). The conductor elements are not loop elements. A tuned conductor element among the conductor elements has a first end at a distance from the antenna element which is lower than &#x3bb;/10, and has a length Hadapted to generate an electromagnetic resonance in the tuned conductor element corresponding to the wavelength &#x3bb;.

A method for transmitting digital data on a communication channel, between a transmitter base comprising N transmission antennas and K receivers. A signal carrier of frequency fand M sub-carriers of index m are used, adapted to transport K streams of digital data sin parallel between the transmitter base and each receiver. The method comprises a step in which N.M complex symbols t(m) are calculated from K.M symbols s(m), by where * denotes a complex conjugate, H(m) is a complex value estimating the transfer function of the communication channel between the transmission antenna n and the receiving antenna k at a corresponding frequency of the sub-carrier m, and &#x3b1;is a normalization coefficient.

Method for transmitting digital data, and transmitter base implementing such a method

Method for focusing an electromagnetic or acoustic wave on a point near which one or more diffusers are placed, comprising a learning step in which the pulsed responses h(t) between the focus point and each antenna of the network are determined. Waves corresponding to signals S(t)=S(t)h(&#x2212;t), where S(t) is a function of time and h(&#x2212;t) is a temporal inversion of the pulsed response h(t), can then be transmitted form said antennas of the network.

Method and device for the transmission of waves

According to the invention, a wave, corresponding to a signal s(t) may be temporally inverted by application of a first transformation to lower the central frequency thereof to produce a first set of transformed signals Ki(t) then a second set of transformed signals K'i(t) is produced representing the temporal inversion signal s(&#x2212;t) and a third transformation is applied to said second set to generate the temporally-inverted signal s(&#x2212;t)

Growing community of inventors

Sevres, France

Arnaud Tourin