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Cuming Microwave is
the only full service supplier in the world offering a complete line of
dielectric, artificial dielectrics, ray domes, RF absorbers and anechoic
chambers for the international aerospace and electronics and defense
industries. |
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High
Performance Pyramidal & Walkway Absorber
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Picture |
Model |
Features |
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C-RAM SFC
HIGH PERFORMANCE BROADBAND RF ABSORBER
PYRAMIDAL
120 MHz - 50 GHz
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C-RAM SFC is a series of high performance broadband RF
absorbers made from specially treated low density polyurethane foam. The
product is flexible and tolerant of physical abuse. Using a steep pyramid
design which provides an impedance gradient, C-RAM SFC provides premium
performance in anechoic chambers at both normal and off-normal incidence
angles. These products meet all of the fire retardancy requirements of NRL
Specification 8093 tests 1, 2, and 3, MS-8-21 tests 1, 2, and 3, and T.I.
drawing 2693066, as well as ASTM E-84-97a, Class A |
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C-RAM SFC-WW
HIGH PERFORMANCE BROADBAND RF ABSORBER
WALKWAY
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C-RAM SFC-WALKWAY is a series of high performance broadband RF absorbers, fabricated from standard C-RAM SFC pyramidal absorber. The SFC
absorber is fit with a low density polystyrene foam matching section to
square the piece off, and the sides and top of the block are fit with a half
inch (13mm) thick sheeting of fire retardant polyvinyl chloride (PVC) rigid
foam.
Walkway absorber provides an effective access path for
servicing the transmit and receive areas of an anechoic chamber. 
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C-RAM SFC PYRAMIDAL & WALKWAY PHYSICAL
CHARACTERISTICS
TYPICAL REFLECTIVITY AT NORMAL INCIDENCE (dB)
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Model |
Absorber Height
in. (mm) |
Walkway
Overall Height
in. |
Weight
lb. (kg)
Walkway (2.5 x below) |
Tips /
Piece |
Absorption
at Freq. (GHz) |
|
.12 |
.3 |
.5 |
1 |
3 |
6 |
10 |
18 |
*36 |
*50 |
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SFC-3 |
3.0 (76) |
NA |
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256 |
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26 |
32 |
39 |
45 |
50 |
50 |
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SFC-4 |
4.3 (109) |
7.3 |
3.0 (1.4) |
144 |
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30 |
35 |
42 |
50 |
50 |
50 |
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SFC-6 |
6.0 (152) |
9.0 |
3.5 (1.6) |
100 |
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32 |
40 |
45 |
50 |
50 |
50 |
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SFC-8 |
8.0 (203) |
11.0 |
4.5 (2.0) |
64 |
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30 |
37 |
45 |
50 |
50 |
50 |
50 |
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SFC-12 |
12.0 (305) |
15.0 |
6.0 (2.7) |
36 |
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35 |
40 |
45 |
50 |
50 |
50 |
50 |
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SFC-18 |
18.0 (457) |
21.0 |
12.0 (5.4) |
16 |
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30 |
37 |
40 |
45 |
50 |
50 |
50 |
>45 |
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SFC-24 |
24.0 (610) |
27.0 |
17.0 (7.7) |
9 |
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30 |
35 |
40 |
45 |
50 |
50 |
50 |
50 |
>45 |
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SFC-36 |
36.0 (914) |
39.0 |
24.0 (10.9) |
4 |
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35 |
37 |
42 |
50 |
50 |
50 |
50 |
50 |
>45 |
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SFC-40 |
40.0 (1016) |
43.0 |
39.0 (18) |
4 |
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35 |
38 |
43 |
50 |
50 |
50 |
50 |
50 |
50 |
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SFC-48** |
48.0 (1219) |
51.0 |
38.0 (17) |
2 |
28 |
35 |
40 |
50 |
50 |
50 |
50 |
50 |
50 |
>45 |
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SFC-72** |
72.0 (1829) |
75.0 |
50.0 (23) |
1 |
33 |
40 |
45 |
50 |
50 |
50 |
50 |
50 |
50 |
>45 |
* SFC has been characterized at 36 and 50 GHz, but is not routinely measured
at these frequencies.
** SFC-48 and -72 are generally supplied in the "twisted" configuration.
The base of the SFC-48 is 18 x 36" (457 x 914 mm). The SFC-72 has the
standard 24" (610 mm) base.
Reflectivity performance of a walkway is degraded from that of the SFC
absorber comprising it, due to reflections from the PVC skin. The
degradation becomes more significant with increasing frequency; below 1GHz,
the degradation is small, at 10 GHz, reflectivity is limited to about 25 dB,
in mm-wave applications, other methods of accessing equipment should be
considered, such as removing and replacing absorber before beginning
testing.
C-RAM SFC WALKWAY can be made from any grade of the standard
SFC absorber, but SFC-24 is the largest standard size. Pieces are generally
24 in x 48 in (610 x 1220 mm), or 24 in x 24 in (610 x 610 mm). Other custom
sizes can be made, as well as steps, ramps, and cutouts for pedestals.
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High
Performance Wedge Absorber
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Picture |
Model |
Features |
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C-RAM SFC-W
HIGH PERFORMANCE RF ABSORBER
WEDGE SHAPED
500 MHz - 50 GHz
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C-RAM SFC-WEDGE is a series of high performance broadband absorbing materials of wedge configuration. SFC-WEDGE complements the
pyramidal SFC product, and is made using the same process and materials. SFC-WEDGE
therefore possesses the same desirable properties, including fire retardancy
compliance with NRL-8093 Tests 1, 2 and 3. |
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C-RAM SFC WEDGE PHYSICAL DATA
TYPICAL REFLECTIVITY AT NORMAL INCIDENCE (dB)
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Convoluted Microwave Absorber
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Picture |
Model |
Features | |
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C-RAM FAC
HIGH PERFORMANCE
BROADBAND
MICROWAVE ABSORBER
CONVOLUTED
3 GHz - 77 GHz
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C-RAM FAC is a series of high performance broadband microwave absorbers, made from light weight, very flexible urethane foam treated with a dielectric lossy material, which also imparts great fire retardancy. The product meets NRL 8093.
C-RAM FAC is a convoluted product; the front face is rippled or convoluted like an egg carton, the convolutions provide an impedance taper, which is very effective in minimizing front face reflections, especially at higher frequencies. |
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TYPICAL DIMENSIONS
REFLECTIVITY PERFORMANCE (dB) |
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3GHz |
6GHz |
10GHz |
15GHz |
30GHz |
77GHz |
Height
in. (mm) |
Weight
lb. (kg) |
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FAC 1.5 |
- |
20 |
30 |
35 |
40 | |
1.5 (38) |
1 (0.45) |
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FAC 3.0 |
20 |
30 |
40 |
45 |
50 |
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3.0 (64) |
1.8 (0.82) |
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FAC 4.0 |
25 |
30 |
40 |
45 |
50 |
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4.0 (102) |
2.3(1.1) |
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Convoluted, Reticulated Foam Absorber
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Picture |
Model |
Features | |
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C-RAM
RFC (Flow Through)
RFA (Outdoor)
HIGH PERFORMANCE
BROADBAND
MICROWAVE ABSORBER
CONVOLUTED
2 GHz - 50 GHz
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C-RAM RFC is a series of RF absorbers optimized for performance at frequencies above 10 GHz. Made from a very uniform, open-cell, small pore urethane foam, C-RAM RFC works well up to and above 50 GHz, and meets the fire retardancy requirements of NRL 8093. The material is intended primarily for indoor use in anechoic chambers and other test facilities.
C-RAM RFC is very similar in construction and performance to the analogous convoluted absorber, C-RAM FAC. C-RAM RFC would be used when air flow through the piece is required, such as over an air duct, or for cooling air in a high power application.
C-RAM RFA is a similar convoluted absorber available in various thickness grades. It is made from a large-pore open-cell urethane foam (approx 15 pores/inch). This open cell structure makes C-RAM RFA ideal for outdoor applications, where rain can drain quickly through the piece, and residual moisture can evaporate quickly. | |
TYPICAL DIMENSIONS AND REFLECTIVITIES (dB)
OF C-RAM RFC
TYPICAL DIMENSIONS AND REFLECTIVITIES (dB)
OF C-RAM RFA
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