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Recently as information communication
systems continue to become wireless, various
radio waves are present in offices, medical institutions
and public transportation facilities, and etc.
Wireless network users, especially, are rapidly
increasing due to permeation of such technologies
as wireless LAN and wireless IP phones.
In offices with numerous wireless communication
devices, reflection of radio waves against
walls, ceilings and fixtures made of metal
creates multipath problems that reduce communication
speed.
In addition, there is an increasing need for radio wave leakage
measures in conjunction with the Personal Information Protection
Law. |
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| Nitta's PFN series radio wave absorbers
that remove unnecessary radio waves, such as reflection,
multipath, etc., to provide a wireless communication
environment with limited loss of communication
speed and radio wave leakage. |
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| Feature: |
When
compared with a conventional
ferrite rubber sheet (6.5
mm, 15 kg/m2),
it is 1/2 the thickness,
1/3 the weight and more
flexible. |
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| Feature: |
Excellent
electromagnetic wave absorption
characteristics, over 15
dB at 10° for
TE and TM, excellent oblique-incidence
characteristics |
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| Feature: |
Easily
formed construction including
cutting at installation.
Can be made flame resistant
and/or non-halogen. |
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| (Patent
Number: 3647447) |
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| Patterned
Absorption Sheet |
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Improves wireless
LAN communication |
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Improves IC Tag communication |
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Adds some electromagnetic wave
shielding characteristics |
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Improves communication for
ETC, DSRC (5.8 GHz band) and others |
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| Incoming
Angle |
TE
(dB) |
TM
(dB) |
| 10° |
21 |
21 |
| 30° |
17 |
19 |
| 45° |
13 |
17 |
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* Can be designed to
accommodate designated frequencies. (*1)
* TE and TM absorption performance at oblique
incidence of 10° (*2)
* Figures above are neither standard nor
guaranteed values.
* Please contact us about the dimensions
of products not shown in this chart.
* The flame retardance of the PFN20 is equivalent
to that of the UL94V0. |
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| Electromagnetic waves are converted
to thermal energy then absorbed by the absorber. |
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The pattern captures electromagnetic
waves with a specific frequency and incorporates
them into the sheet.
By having an absorption layer between the pattern layer and
reflective layer, radio waves are efficiently absorbed in spite
of the thinness. |
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Office
space dimensions
2.1 m high and 3 m x 3 m floor space (Maximum space that can
be simulated with 1 GB main memory on the PC used) |
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| In this simulation, a
steel bookcase at two corners and aluminum
partition boards surrounding desks
are placed. |
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A wireless
LAN (2.4 GHz band) access point antenna
is placed 2 m above the center of desk
D. |
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Standing wave is observed
within each partition boards, confirming
the presence of electromagnetic interference.
The electromagnetic field weakens as the distance from
the access point increases. It suggests that depending
on antenna position of the PC, reception may not be possible. |
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A radio wave
absorber at 15 dB is placed at desks and
partition boards. |
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Standing wave disappears,
and uniform distribution of electric
field is observed.
This indicates suppression of electromagnetic interference. |
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| Cited Reference |
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Author: Hiroaki Kogure
Source: Design Wave Magazine, CQ Publishing Co., Ltd. July 2005 P.
31 |
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| *This material was posted courtesy
of Dr. Hiroaki Kogure at Kogure Consulting Engineers. |
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