Device for electromagnetic dosimetry and associated method

Abstract

Some embodiments relate to a device for simulating characteristics of human tissues in electromagnetic dosimetry. The device includes a substrate bearing a metallised shielding, a layer of a dielectric material arranged on or preferentially beneath the substrate and the device including a plurality of openings made in the shielding and at least one array of sensors in the layer of dielectric material.

Claims

1. A device for electromagnetic dosimetry, comprising: a shielding that defines a plurality of openings; a layer of substrate, bearing the shielding; a layer of a dielectric material arranged on and/or beneath the layer of substrate; and at least one array of sensors in the layer of dielectric material, wherein the plurality of openings are calibrated to provide to the shield an electromagnetic reflectivity of an upper part of a phantom which contributes to the simulation of the reflection characteristics of human tissues, wherein the at least one array of sensors include one or a plurality of antennas and/or probes, the at least one array of sensors being suitable for receiving signals transmitted by a source situated on the other side of the shield, wherein the dielectric material includes plastic or glass or polymer and the plurality of openings are arranged in a thickness of the shielding to provide a relative transparency to the signal transmitted from the source, wherein the at least one array of sensors are arranged on the side of the layer of substrate opposite the source.

2. The device according to claim 1, wherein the substrate is essentially made of organic or synthetic polymer or resin.

3. The device according to claim 1, wherein the openings in the shielding are made in slot, or square, circular, triangular or oval shapes, and are arranged regularly in the thickness of the shielding.

4. The device according to claim 1, wherein the greatest of the dimensions of the openings has a value between a fraction of the wavelength and some ten wavelengths.

5. An electromagnetic dosimetry method, comprising: emitting electromagnetic signals at a frequency preferentially greater than 6 GHz, from a source arranged at a predetermined distance from a device for electromagnetic dosimetry according to claim 1; and measuring, using at least one array of sensors arranged in or against the layer of dielectric material, on the side of the substrate opposite the source.

6. The method according to claim 5, wherein the predetermined distance between the source and the device, is within a range of values ranging from 0 millimeters to 100 centimeters, these limit values being included in the range.

7. The device according to claim 2, wherein the openings in the shielding are made in slot, or square, circular, triangular or oval shapes, and are arranged regularly in the thickness of the shielding.

8. The device according to claim 2, wherein the greatest of the dimensions of the openings has a value between a fraction of the wavelength and some ten wavelengths.

9. The device according to claim 2, wherein the sensors include antennas and/or probes.

10. The device according to claim 3, wherein the sensors include antennas and/or probes.

11. The device according to claim 4, wherein the sensors include antennas and/or probes.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Some embodiments will be understood more clearly, and further specificities and advantages will emerge on reading the following description, the description referring to the appended drawings wherein:

(2) FIG. 1 represents a simulation device configured for electromagnetic dosimetry according to the related art.

(3) FIG. 2 represents a simulation device configured for electromagnetic dosimetry at frequencies in the 60 GHz band for example according to a particular and non-limiting embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

(4) In FIGS. 1 and 2, the modules represented are functional units, optionally corresponding to physically distinguishable units. For example, these modules or some thereof are grouped into a single component. On the other hand, according to further embodiments, some modules are composed of separate physical entities.

(5) FIG. 1 represents a device A for simulating characteristics of human tissues configured for electromagnetic dosimetry according to the related art. The device A includes a layer of dielectric material DLPA based on water or gel (including a polymer for example) and which includes an array SA of sensors SENS in the layer DLPA.

(6) The device in FIG. 1 is suitable for evaluating the exposure of the human body to one or a plurality of antennas emitting signals at a frequency less than or equal to 6 GHz in the vicinity thereof. The dielectric properties of the phantom device are adjusted to represent those of the human tissues in a given frequency range.

(7) Unfortunately, in the absence of a shell, this type of phantom is degraded over time, due in particular to an evaporation phenomenon in the layer of dielectric materials DL.

(8) FIG. 2 represents a device configured for electromagnetic dosimetry according to a particular and non-limiting embodiment and at frequencies greater than 6 GHz and typically around 60 GHz.

(9) Cleverly, the substrate S bears a shielding MSH acting as a reflector and including preferentially calibrated openings (or holes) OSH and which advantageously provide electromagnetic reflectivity (and transparency) of the upper part of the phantom A which contributes to the simulation of the reflection characteristics and to a lesser degree the absorption characteristics of human tissues, and particularly the epidermis, dermis and adipose tissues situated below the dermis, at frequencies around 60 GHz.

(10) At these frequencies (above 6 GHz), the absorption of radiation is limited to the superficial layers of the body: at 60 GHz, the penetration depth of electromagnetic radiation in the tissues is of the order of 0.5 mm; the absorption is therefore essentially concentrated in the skin. The epidermis absorbs approximately 30% of the power and the dermis absorbs approximately 69% thereof and the remainder is absorbed by adipose tissues.

(11) Advantageously, the measurement method which uses the phantom A in FIG. 2 includes a step for the emission of electromagnetic signals at a frequency preferentially greater than 6 GHz, and even more preferentially greater than 10 GHz, from a source EMS arranged at a predetermined distance dl (not shown) of the device A for electromagnetic dosimetry including the substrate S bearing the metallised shielding MSH, the shielding MSH including a plurality of calibrated openings OSH, and the device A including the layer DL of a dielectric material arranged beneath the substrate S.

(12) The method includes also and above all a measurement, using at least one array SA of sensors SENS each including one or a plurality of antennas and/or probes and arranged in the layer DL of dielectric material, on the side of the substrate S opposite the source EMS.

(13) Advantageously, this is enabled due to the formation of the calibrated openings OSH in the metallised shielding MSH, arranged along the substrate S of the device A.

(14) The substrate S of the device A is made, according to one particular and non-limiting embodiment, of polydimethylsiloxane, which includes carbon black powder.

(15) The openings OSH are made in slot, or square, circular, triangular or oval shapes and are preferentially arranged in the thickness of the shielding MSH so as to provide a relative transparency to the electromagnetic radiation from the source EMS used.

(16) According to the method, the predetermined distance dl is between 0 and 100 cm, that is possibly in direct contact with the phantom A.

(17) All of the details of the technical operations for defining the signals emitted and analysing the signals extracted by the array (or arrays) of sensors are not detailed further herein, as they are well-known to those of ordinary skill in the art.

(18) According to one alternative embodiment, a layer of dielectric material DL may be arranged on the surface of the substrate S. The dielectric material of this layer DL may be identical to that of the layer DL, or different.

(19) Advantageously, the substrate S and the layer of dielectric material DL may be of planar shape or of any shape, to simulate all of part of the human body, for example. This applies in the same way for the shielding.

(20) According to one alternative embodiment, an array of sensors SENS similar to the array of sensors SA is placed in the metallised shielded substrate, in addition to the array situated in the layer of dielectric materials DL.

(21) Advantageously, this makes it possible to obtain a better assessment of the waves absorbed at different depths of the phantom and therefore at different depths of human biological tissues and particularly of the epidermis, dermis and adipose tissue situated beneath the dermis.

(22) According to a further alternative embodiment, a plurality of layers of dielectric materials similar to DL, each having a different permittivity are stacked and include one or a plurality of arrays of sensors so as to evaluate the absorption of electromagnetic radiation at different depths of the epidermis and dermis.

(23) Some embodiments are not limited solely to the embodiment described above but relates obviously to any device for simulating reflection and absorption characteristics of the human body for electromagnetic dosimetry, including a substrate bearing a shielding, optionally metallised, and a layer of a dielectric material arranged on and/or beneath this substrates, and for which the shielding includes a plurality of calibrated openings; the device including at least one array of sensors positioned in the layer of dielectric material. Some embodiments also relate to any method using a device as described in the lines above.