2673021801 Fair-Rite, 2673021801 Datasheet - Page 183

• Manufacturer Part Number: 2673021801
• Description: EMI/RFI Suppressors & Ferrites Z=94ohms @ 10MHz
• Manufacturer: Fair-Rite

Specifications of 2673021801

• Shielding: Unshielded
• Test Frequency: 100 MHz
• Product: Ferrite Beads
• Impedance: 95 Ohms
• Operating Temperature Range: - 55 C to + 125 C
• Termination Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

14th Edition
P.O. Box J,One Commercial Row, Wallkill, NY 12589-0288
Phone: (888) FAIR RITE / [phone]
Introduction
Fair-Rite’s tile absorbers provide an attractive alternative to
traditional large, foam-type absorber materials for new anechoic
chambers or for upgrading older rooms for radiated emission
and immunity measurements. While ferrite tiles are a relatively
recent development, they have come into use wherever high
absorption (-15 to -25 dB at <100 MHz) and compact size (6mm
vs 2400mm for foam absorbers) are required. There are now
hundreds of installations worldwide in compact and 3/10 meter
FCC certified chambers. Ferrites themselves are inherently
immune to fire, humidity and chemicals providing a reliable
and compact solution for attenuating plane wave reflections in
shielded enclosures.
Theory of Operation
The basic physics of operation for any planar electromagnetic
absorber involves fundamental concepts as shown in Figure 1.
When an electromagnetic wave traveling through free-space
encounters a different medium (at Z=0), the wave will be re-
flected, transmitted, and/or absorbed. It is of course, the magni-
tude of the reflected signal which is usually of interest in this
application. For ferrite tiles, the thickness is tuned so that the
relative phases of the reflected and exiting wave cancel to form
a resonant condition. This resonant condition appears as a deep
“null” in the return loss response. This resonance is also a
function of the frequency dependent electrical properties of the
ferrite material such as relative permeability (m
(e
impedance (Z) and return loss (RL) according to the following
formulas:
Ferrite Tile Absorbers
for EMC Test Chamber Applications
G =
RL = 20 log
r
Z
) which interact to determine the reflection coefficient (G),
f
=
Z
Z
[phone]
f
f
+ Z
- Z
m
e
r
0
0
r
10
• tanh
(G)
[(
(dB)
j2 pd
l
)(
m
r
e
r
)]
r
) and permittivity
• FAX: (888) FERRITE / [phone] • www.fair-rite.com • E-Mail: [e-mail]
Technical Information
(ohm)
[phone]
Fair-Rite Products Corp.
Figure 1
Where :
Increasing Bandwidth
For some chamber applications increased absorber bandwidth
may be desired to comply with high frequency testing needs. One
technique shown in Figure 2 increases the bandwidth of ferrite
tile installations by mounting the tile over a dielectric spacer
(typically wood) of appropriate thickness. When both tile and
spacer thicknesses are optimized, the frequency response is
shifted upward to improve return loss performance from 600-
1500 MHz (see Figure 3). Of course, if increased bandwidth up
to 20 GHz is desired, several absorber vendors provide com-
pletely engineered hybrid absorbers using specially designed
pyramidal and wedge shaped dielectric absorbers matched to
ferrite tiles.
E
E
E
Reflected
i
r
t
Incident
,H
,H
,H
Z
m
m
Z
Note: (914) Area Code has changed to (845).
e
e
G = reflection coefficient of metal backed ferrite tile
d = thickness of medium 2 (ferrite)
wave
wave
1
2
o
1
2
f
i
r
t
= relative permeability of medium 1 (air)
= relative permittivity of medium 1 (air)
= relative permeability of medium 2 (ferrite)
= relative permittivity of medium 2 (ferrite)
= input impedance of metal backed ferrite tile
= impedance of free space (air)
= components of incident plane wave
= reflected components of incident plane wave
= transmitted components of incident plane wave
a nr
H r
Medium 1
H i
(e 1 , m 1 )
E r
E i
a ni
z – 0
x
y
Medium 2
(e 2 , m 2 )
H t a nt
z
E t
Transmitted
wave
Metallic
Surface
183