| Nippon Paint develops
ultra-light and thin electromagnetic absorber
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| 3-layer configuration achieves an exceptionally
thin design |
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| Nippon Paint Co., Ltd. has developed a ultra-light
and thin electromagnetic absorber in a three-layer configuration.
This innovative material consists of three layers -- a thin
metal film layer, a foamed spacer layer and a conductive film
layer. With target frequency set to wireless LAN (2.45GHz),
the absorber measures a mere 2.2mm, weighs just 400g per square-meter,
and absorbs over 15dB of unnecessary microwaves. The target
frequency band to be absorbed can be selected between 1 to 15GHz,
accommodating various applications such as wireless LAN (2.45GHz),
aerial radar (1.0GHz), automatic fare collection systems (5.8GHz)
and marine radar (9.3GHz). Depending on the application, this
material contributes to enhancing the communication environment
by reducing electromagnetic interference. |
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| Product structure |
| Layer
1 |
Fine
metal pattern film using resist technology (38 microns) |
| Layer
2 |
Spacer
comprised of foamed material (several millimeters, variable
with frequency used) |
| Layer
3 |
Electric
wave reflection layer comprised of conductive film (35
microns) |
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| Product features |
| * |
Unprecedentedly
thin and lightweight design. |
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| * |
Highest reflection
loss (over 15dB) |
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| * |
User-selectable
frequency band depending on the application |
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| Application |
 |
Absorbing
frequency |
Weight
(g/m2) |
Thickness |
Reflection
loss |
| Aerial
radar |
1.0GHz |
900g |
5.2mm |
Over
15dB |
| Wireless
LAN (mid-speed) |
2.45GHz |
400g |
2.2mm |
Over
15dB |
| Automatic
fare collection system |
5.8GHz |
350g |
0.9mm |
Over
15dB |
| Marine
radar |
9.3GHz |
300g |
0.4mm |
Over
20dB |
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| Thickness and weight comparison |
| Conventional wireless LAN-use absorbers
are either "light but thick" or "thin but heavy." |
|
Weight
(kg/m2) |
Thickness |
Reflection
loss |
Characteristics |
| Conventional
ferrite rubber |
19kg |
6.3mm |
Over
25dB |
Thin
but heavy |
| Conventional
impedance-matching absorber material |
2kg |
30.0mm |
Over
25dB |
Light
but thick |
|
Nippon Paint absorber (for wireless LAN) |
0.4kg |
2.2mm |
Over
15dB |
Light
and thin |
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| Electromagnetic absorbing mechanism |
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Originally discovered through
a study headed by Dr. Yoshiyuki Naito, President of the Tokyo
Institute of Technology, this material features an exceptionally
thin design -- less than 1/10th of a conventional lambda/4 impedance-matching
absorber. Although its electromagnetic absorbing mechanism is
yet to be theoretically uncovered, it is assumed that a certain
frequency band that enters the absorber resonates (without being
radiated) and is converted into thermal energy. Continued theoretical
study for the discovery of a mechanism is being planned.
* Principles of electromagnetic absorbing
mechanism include dielectric loss, magnetic loss and mixed types.
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| Applications |
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| * |
Attachment
to indoor walls, ceiling boards, partition boards
and metallic cabinets of offices and laboratories
that frequently use wireless equipment. |
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| « |
Thin, lightweight
and easy to cut with scissors. |
| « |
Wall paper
and cloth may be pasted over (paint may not
be applied). |
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| * |
Besides indoor
use, production of other versions designed for building
exteriors and furniture is being planned. |
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| Future direction |
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| Ready for mass-production, Nippon Paint
will strengthen and promote a market launch of its product lines
for wireless offices by adding this innovative material to currently
available indoor-use electromagnetic absorbing boards and selective
shielding films. |
