Impact of Textile on Electromagnetic Power and Heating in Near-Surface Tissues at 26 GHz and 60 GHz

[miquelangeles]

Take-Home Messages​

• This study provides, for the first time, a detailed quantitative analysis of the electromagnetic power absorption and temperature elevation in presence of a textile at 26 GHz and 60 GHz, frequencies upcoming for 5th generation (5G) and next generations of wireless communications systems.
• We demonstrate that a textile in contact or in proximity of skin impacts the power deposition and the consequent temperature elevation; in particular, cotton and wool in contact with skin increase the absorbed power density up to 41.5% at 26 GHz and 34.4% at 60 GHz.
• The interest of this study is to evaluate the exposure in the upcoming 5G bands in the scenarii involving interaction of electromagnetic fields in presence of a textile layer (e.g. usage of a tablet lying on the user’s legs or of radiating devices during wintertime, when wearing hats or gloves).
• We analysed and quantified, for the first time, the power absorption and temperature elevation at 26 GHz and 60 GHz in presence of some of the most common textiles used for clothes (i.e. cotton and wool).
• We demonstrate that with the textile in direct contact with skin the temperature rise increases compared to the bare skin by up to 52% at 26 GHz and 46% at 60 GHz and that, with an air gap and for typical textile thicknesses, the variation ranges from −3.5% to 20.6% and from −11.1% to 20.9% at 26 GHz and 60 GHz, respectively

Abstract​

With the development of 5th generation (5G) networks the operating frequencies have been progressively expanding towards millimeter waves (MMW). In some exposure scenarii, presence of textiles impacts the interaction of the electromagnetic field radiated by wireless devices with human tissues. We investigate the impact of a textile layer in contact or in proximity of skin on the power transmission coefficient, absorbed power density and temperature rise using a near-surface tissue model at 26GHz and 60 GHz. Cotton and wool are considered as representative textiles. Our results demonstrate that the textile in contact with skin increases the absorbed power density up to 41.5% at 26 GHz and 34.4% at 60 GHz. The presence of an air gap between a textile and skin modifies the electromagnetic power deposition in the tissues depending on the thicknesses and permittivity. The temperature rise increases compared to the bare skin by up to 52% at 26GHz and 46% at 60 GHz with the textile in direct contact with skin. With an air gap, for typical textile thicknesses, the temperature variations range from −3.5% to 20.6% and from −11.1% to 20.9% at 26GHz and 60 GHz, respectively.

 

[Vileplume]

If I understand correctly, do these clothing materials act as a conductor of the electromagnetic power from 5G? I wonder how they would amplify the strength and heating effect.

 

[Dapose]

When I visualize this phenomenon in my mind it is that the fabric (textile, who uses that word?) concentrates the frequencies. Like static electricity built up when you where socks across carpet. Not amplifying it but collecting it.
Anyway, this study definitely shows why cellphone always gets so hot in my pocket. I still try and not do that but I am terrible about leaving it in my side pant pocket.
Thanks for posting this.

 

[Dapose]

I wish they would have checked polyester fabrics since those are so much more prevalent in our modern cheap clothing.
And they have a worse static electricity build up from my estimation.