Datasheet

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EMI ESSENTIALSEMI ESSENTIALS
Q-ZORB
®
2000 HF (HIGH FREQUENCY)
SURFACE WAVE ABSORBERS
Q-Zorb
®
2000 HF surface wave absorbers are thin,
magnetically loaded elastomeric sheets designed to
provide attenuation at high angles of incidence for surface
wave attenuation. They are nominally manufactured in
the thickness range of 0.015" to 0.125" (0,4 mm to 3,2
mm). Q-Zorb
®
2000 is silicone-based, meets the UL V0
re retardant requirement and is RoHS compliant. Laird
can provide the material die-cut and with a pressure-
sensitive adhesive for ease of installations. Sheets are
offered in nominal sizes of 24" x 24" (609,6 mm x 609,6
mm), although custom sizes and molded components are
available.
APPLICATIONS
The material can be used inside of microwave housings
to reduce internal resonance and to lower the "Q" of
the microwave cavity. They are also effective in isolating
antennas from ground plane reections. Q-Zorb
®
can
be used with board-level shielding and other types of
EMI shielding to enhance the shielding effectiveness at
frequencies from 2-40 GHz.
FIGURE 3.
Q-Zorb Surface Wave 0.040" (1.0 mm) Thick
P/N 2238
2
4
6810 12 14 1816
Frequency (GHz)
Loss (dB)
0
-5
-10
-15
-20
-25
-30
-35
FIGURE 1.
FIGURE 2.
Q-Zorb Surface Wave 0.060" (1.5 mm) Thick
P/N 2240
2
4
6810 12 14 1816
Frequency (GHz)
Loss (dB)
0
-5
-10
-15
-20
-25
-30
-35
Reection Loss (dB)
Reection Loss (dB)
Reection Loss (dB)
Reection Loss (dB)
Frequency (GHz)
Frequency (GHz)
Frequency (GHz)
Frequency (GHz)
Q-Zorb .020 in (0.5 mm) Thick
P/N 2388
Q-Zorb 0.040 in (1.0 mm) Thick
P/N 2238
2 4 6 8 10 12 14 16 18
1
-1
-3
-5
-7
-9
-11
-13
-15
2 4 6 8 10 12 14 16 18
0
-5
-10
-15
-20
-25
-30
-35
PART NO. SIZE THICKNESS WEIGHT
TEMPERATURE
MAXIMUM
ELECTRICAL
PERFORMANCE
COLOR BONDING
FIRE RETARDANT
RATING
2388 24” x 24”
0.20”
nominal
(.5 mm)
.50 lb/sq ft 300 °F 12-18 GHz Gray
RoHS Compliant
Sulfur-free
Supplied with
3M 9485 PSA
UL V0
2388 -.25 12” x 12”
2388 - S 4” x 6”
2238 24” x 24”
.040”
nominal
(1 mm)
.94 lb/sq ft 300 °F 8-18 GHz Gray
Good general
weather and chemical
resistance Sulfur-free
Supplied with
3M 9485 PSA
UL V02238 -.25 12” x 12”
2238 - S 4” x 6”
2240 24” x 24”
0.60”
nominal
(1.5 mm)
1.2 lb/sq ft 300 °F
4-18 GHz
Excellent for surface
current attenuation
Gray
Good general weather
and chemical resistance
Sulfur-free
Supplied with
3M 9485 PSA
UL V02240 -.25 12” x 12”
2240 - S 4” x 6”
2242 24” x 24”
.125”
nominal
(3.2 mm)
2.75 lb/
sq ft
300 °F
1-18 GHz
Excellent for surface
current attenuation
Gray
Good general weather
and chemical resistance
Sulfur-free
Supplied with
3M 9485 PSA
UL V02242 -.25 12” x 12”
2242 - S 4” x 6”
Q-Zorb .125 in (3.2 mm) Thick
P/N 2242
All dimensions shown are in inches (millimeters) unless otherwise specied.
Q-Zorb Wave 0.060 in (1.5 mm) Thick
P/N 2240
FIGURE 4.
DBR vs FGHZ A01 = 0
DBR vs FGHZ A01 = 0
TUNED FREQUENCY
VS SURFACE WAVE ABSORBERS
Laird offers two types of Q-Zorb materials: tuned frequency and
surface wave absorbers. Tuned frequency materials are used
in far eld applications such as direct radar reections off of
an object. Surface wave absorbers are used for high angle of
incidence applications and for cavity noise suppression. Many
design engineers that have a cavity noise problem at a certain
frequency want to use a tuned frequency absorber tuned to that
frequency. However that is not the best performance they can
achieve. Note that the tuned frequency materials offer good
performance at normal angles of incidence, but perform more
poorly at higher angles of incidence. Inside the cavity noise
generated is at a number of angles of incidence and also a
signicant of surface wave energy. The surface wave materials
offer better performance in these applications. The curves below
compare a tuned frequency absorber at normal incidence and
at all angles of incidence. Note the improved bandwidth of the
surface wave loading especially at higher angles of incidence.
The Q-Zorb samples in the Laird Absorber sample kit are the
surface wave absorber type. They are the best solution for solving
cavity noise problems.
DESIGN GUIDE FOR
COMMERCIAL MICROWAVE ABSORBERS
EMI MODELING
Laird is a member of the EMC Consortium at Missouri Science
and Technology School, Rolla Missouri. As part of this consortium
Laird is modeling the use of absorbers for a variety of applications.
The cavity application discussed above is one of the key areas of
investigation. Other areas include directly placing absorbers on
noisy chips, coating cables to reduce conducted EMI, and use on
antennas. Laird is working on modeling these applications using
3D modeling software including HFSS, Microwave Studio, and
EZ-FTDT. The Q-Zorb can be modeled as a Debye Oscillator and
directly input into the codes. Laird can supply these models to
customers for their own computer modeling. A few examples of
this work are shown in the gures below.
Figure 7. Microwave CST Model of Cable with Q-Zorb Coating
SAMPLE KIT
To assist the microwave design engineer in the use of Laird
absorbers, a sample kit containing the different types of
microwave absorbers is offered. The kit contains all three types of
materials including Q-Zorb HF, Q-Zorb HP, and RF Foam.
A description of the sample kit is listed below.
The samples are 6”x 4” in size and can be easily cut into specic
shaped pads. There are various thicknesses to evaluate. Generally
speaking the thicker the sample the better it will work at low
frequency. However if you are constrained by thickness, evaluate
the one that will meet the thickness requirements and then test
the electrical properties of the sample. To make even thicker test
samples the samples can be bonded together. This will allow the
designer to evaluate thickness vs performance.
PART
NUMBER
DESCRIPTION THICKNESS
FREQUENCY
RANGE
2388 Q Zorb™ - RFSW .020” (0.5 mm) >10 GHz
2238 Q Zorb™ - RFSW .040” (1.0 mm) > 8 GHz
2240 Q Zorb™ - RFSW .060” (1.5 mm) > 4 GHz
2242 Q Zorb™ - RFSW .125” (3.1 mm) < 4 GHz
3535 CA-19 .006” (0.15 mm) < 2 GHz
3536 CA-19 .020” (0.5 mm) < 2 GHz
5206 RF Foam - RFLS .125” (3.1 mm)
Insertion Loss
Broadband
5092 RF Foam - RFLS .250” (6.25 mm)
Insertion Loss
Broadband
4106 RF Foam - RFRET .50” (12.5 mm)
Insertion Loss
Broadband