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Flat Foam Radar Absorber
    

Cuming Microwave Flat Foam Absorber

PPG Cuming Microwave Logo

Cuming Microwave Corporation is at the forefront of innovative microwave absorber technology and materials for the RF Electromagnetic Interference, Radar Cross Section Reduction and Anechoic Chamber markets. From dielectric, artificial dielectrics, radomes, RF absorbers, and anechoic chambers for the international aerospace, electronics, and defense industries. From thin resonant absorption sheets to 12 foot pyramids to radar reflectors for mach speed aircraft; from do-it-yourself anechoic test chambers to turnkey anechoic chambers.

Cuming Microwave is a ISO 9001 Certified Manufacturer

Made in the USA

ROHS

     

Cuming Flexible Flat Foam RF & Microwave Absorber

 

C-RAM LF

 

Available in 2 Weatherproof Versions

 

FLEXIBLE FOAM SHEET

BROADBAND MICROWAVE ABSORBER

Multi-Layer Graded Carbon

 

Flexible Foam

600 MHz - 40 GHz

 

Cuming LF Flat Foam Absorber

 

 

Data 

 

 

C-RAM LF is a series of lightweight, flexible, broadband radar absorbers made from graded layers of lossy open-cell plastic foam. It is designed to provide typically 20 dB of reflectivity reduction in a frequency range dependent upon grade. The product is flexible enough to conform to moderately contoured surfaces. CRAM LF is useful for reducing reflections in radar test ranges, inside radomes, around antennas, and for modifying antenna radiation patterns.

 

It is also available in two weatherproof versions:

C-RAM LF-W is standard LF absorber wrapped in a thin weatherproof fabric tarp. The coating on this tarp is polychloroprene. Color is olive green. For severe weathering conditions, the product can be supplied wrapped in a white colored hypalon tarp which will withstand long term sun and rain exposure, but with a penalty of reduced reflectivity performance.

C-RAM LF-HCN is standard LF absorber wrapped in a thin weatherproof white Hypalon fabric tarp.

Data

Standard product size for all grades of LF are a flat panel 610 x 610 mm (24 x 24 in.).

Other dimensions are possible, including larger parts formed by butt-joining sections together.

 

INSERTION LOSS AND ATTENUATION (C-RAM LF)

Model

Thickness

Weight

Performance

Frequency

 

mm

in

kg

lb

Reflectivity

Range of use

LF-72

6.4

0.25

0.25

0.55

-20 dB

above 18 GHz

LF-73

9.5

0.38

0.40

0.90

-20 dB

above 7.5 GHz

LF-74

19.1

0.75

0.70

1.55

-20 dB

above 3.5 GHz

LF-75

28.6

1.13

0.80

1.75

-20 dB

above 2.5 GHz

LF-77

57.2

2.25

1.50

3.30

-20 dB

above 1.3 GHz

LF-79

114.3

4.50

2.95

6.50

-20 dB

above 0.6 GHz

 

Cuming Reticulated Foam Microwave Absorber

 

C-RAM AR

 

SP - Standard Performance

HP - High Performance

 

BROADBAND

RETICULATED FOAM
RADAR ABSORBER

2 GHz - 40 GHz

 

Cuming Microwave Reticulated Radar Absorber

 

 

Data 

 

 

C-RAM AR is a line of reticulated foam Radar Absorbing sheet materials, comprised of urethane foam and a gradient lossy coating C-RAM AR absorbs microwave energy across a wide range of frequencies. Typically the thicker the material the lower in frequency C-RAM AR will attenuate.

C-RAM AR has proven to be ideal for lining shrouds of communications antennas for the suppression of side lobes. It can also be used to cover fences to separate adjacent antennas, and shield or isolate equipment. The open-cell structure permits airflow freely through the absorber, also when used outdoors rain will freely drain from the product.

Cuming Microwave Corporation offers two types of C-RAM AR, our standard performance AR and high performance AR.

C-RAM AR is available in standard sizes of 24 x 24 in (610 X 610mm) and 24 x48 in. (610 x 1200mm).

Other sizes are available. Cuming Microwave can also supply parts cut to drawings. Consult the factory for alternative sizes.

 

 

Standard Performance (SP) Grade:

Thickness

Performance

Freq. Range

0.375 in.

-12 dB

10 GHz & Up

0.50 in

-12 dB

8 GHz & Up

0.75 in.

-12 dB

6 GHz & Up

1.0 in.

-12 dB

6 GHz & Up

1.25 in.

-12 dB

5 GHz & Up

2.0 in.

-12 dB

3 GHz & Up

Standard Performance (HP) Grade:

Thickness

Performance

Freq. Range

0.375 in.

-20 dB

10 GHz & Up

0.50 in

-20 dB

8 GHz & Up

0.75 in.

-20 dB

6 GHz & Up

1.0 in.

-20 dB

6 GHz & Up

1.25 in.

-20 dB

5 GHz & Up

2.0 in.

-20 dB

3 GHz & Up

 

Cuming Lossy, Carbon Filled, Flexible Flat Foam Microwave Absorber

 

C-RAM MT

 

1/4" to 4.0" High x

24" x 24" (610 x 610 mm)

 

CARBON FILLED

FLEXIBLE FOAM SHEET

1 GHz - 10 GHz

 

Cuming Microwave Flexible Foam Absorber Sheet

 

 

Data 

 

 

C-RAM MT is a series of flexible, lightweight lossy plastic foam sheet materials. A very broad frequency range of dielectric loss is achieved through carbon loading of the foam. C-RAM MT can be used to lower the Q of cavities, attenuate surface currents, absorb stray RF energy, isolate components, and plug areas of RF leakage.


It is a lossy load material; applications requiring a free space reduction of reflectivity should be addressed with C-RAM LF.

C-RAM MT is available in several grades having varying levels of carbon loading, hence varying loss tangents. Each grade is available in a range of thickness. The material is a soft foam and is easily cut with a sharp knife.

Cuming Corporation can also supply C-RAM MT with a peel-and-stick backing, and can die-cut or machine parts to specifications.

 

 

INSERTION LOSS AND ATTENUATION (C-RAM MT)

MODEL

INSERTION LOSS. dB/cm (dB/inch)

ATTENUATION, dB/cm (dB/inch)

 

1 GHz

3 GHz

10 GHz

3GHz

MT-14

0.2 (0.5)

0.4 (1.0)

0.9 (2.2)

0.4 (1.0)

MT-16

0.7 (1.8)

1.5 (3.8)

2.0 (5.0)

1.4 (3.5)

MT-18

0.9 (2.3)

1.8 (4.0)

2.8 (7.0)

1.5 (3.7)

MT-20

1.8 (4.5)

3.2 (8.0)

5.1 (13.0)

3.0 (7.5)

MT-22

2.2 (5.5)

3.9 (10.0)

6.3 (16)

3.7 (9.5)

MT-24

3.5 (14)

11 (32)

24 (60)

11 (27)

MT-26

4.9 (19)

16 (46)

34 (89)

16 (39)

MT-30

16 (40)

24 (60)

43 (110)

19 (49)

NOTE: Insertion loss measurements include the effects of surface reflections; the above values are close to, but not exactly, linear with thickness. For example, a 1/4 inch thick piece has somewhat more than 1/4th as much insertion loss as a one inch thick piece. Attenuation is a measure of loss within a homogeneous material, and does not take into account any reflections at interfaces. It is independent of thickness. This is calculated, not a measured value.

 

Cuming Silicone Rubber Microwave Absorber Sheet Material

 

C-RAM RGD-S

 

Standard product sizes for both grades are flat
sheets 12 x 12 in (305 x 305 mm), available in
several standard thicknesses including:
0.030 in (0.76 mm)
0.040 in (1.02 mm)
0.060 in (1.52 mm)
0.125 in (3.17 mm)
0.250 in (6.35 mm)

1.5 GHz - 10 GHz

 

Cuming RDG-S Silicone Rubber Absorber 

 

 

Data 

 

 

C-RAM RGD-S is a filled silicone rubber microwave absorber sheet material with a high magnetic loss. It is available in three grades: -117, -124 and -192. The -192 grade has higher loading and higher losses.C-RAM RGD-S is used for terminations, loads, and attenuators in waveguides, coaxial lines, and microstrip circuits.

It can also be used for lowering the Q of cavities and eliminating unwanted resonances.C-RAM RGD-S is cut readily with a sharp knife, and can be sawed, die cut, waterjet cut, or otherwise machined to complex shapes. Since it is ferromagnetic, it is easily held in place during machining with magnetic chucks.

It is flexible and can be bonded to contoured surfaces.Because it is flexible, C-RAM RGD-S can withstand temperature cycling when bonded to metals.

The material has good thermal conductivity and can be used to dissipate heat, including that generated by its own magnetic loss mechanism. 

TYPICAL PROPERTIES
Color: Grey
Flammability: non-flammable
Specific Gravity: 4.0
Thermal Expansion per C: 6 x 10-5
Thermal Conductivity: .0021 cal-cm/sec-cm2-C
6.0 BTU-in/hr-ft2-oF
Service Temperature: -55 to +200 C
(-65 to +400F)
Hardness, Shore A: 75
Water Absorption, 24 hrs: <0.1%
Volume Resistivity, ohm-cm: >1010
Dielectric Strength, kV/mm: >400 (>100 V/mil)
Relative Impedance (Z/Zo):

0.3 for -117
0.4 for -124
0.6 for -192

 

ATTENUATION dB/cm

Frequency

LOSS. dB/cm

 

-117 (Z/Zₒ 0.3)

-124 (Z/Zₒ 0.4)

-192 (Z/Zₒ 0.6)

1.5 GHz

2.9

5.6

7

3.0 GHz

11

20

24

8.6 GHz

46

63

70

10 GHz

51

69

80

Note: attenuation is a measure of the absorption of RF energy within the material, and is not the same as insertion loss, which includes reflected energy at the air-material interface

 

Cuming Millimeter Wave Absorber Sheet Material

 

C-RAM MMW

High Frequency Radar Absorber

Standard product sizes for all three grades are flat
sheets 12 x 12 in (305 x 305 mm) and 24 x 24 in (610 x 610 mm), available inseveral standard thicknesses including:

0.040 in (1 mm)

0.125 in (3.17 mm)

0.250 in (6.35 mm)

0.50 in (12.7 mm)

 

18 GHz - 110 GHz

 

 

 

 

Data 

 

 

Cuming Microwave offers various materials that provide excellent absorption at frequencies from 18 GHz to 110 GHz.

The C-RAM MMW absorbers include plastic foam sheet and elastomeric-based materials that have been characterized for peak performance across a wide range of frequencies.

C-RAM MMW has proven to be ideal for side lobe suppression of communication antennas, used to separate adjacent antennas, shield or isolate equipment and Anechoic chamber applications.

The reflectivity of C-RAM MMW varies as a function of thickness and frequency. Standard sheet size is 24x24 for foam and 12x12 for elastomer in thicknesses shown in the chart below.

Non-standard thickness and sizes are available on special order.

TYPICAL PERFORMANCE OF C-RAM MMW-1 LIGHTWEIGHT FOAM
Design Note: (AR)

Thickness Frequency Reflectivity
0.50 26 to 110 GHz >20dB
0.25 70 to 110 GHz >20dB

TYPICAL PHYSICAL PROPERTIES
Color: Black
Density: 3.2kg/m (0.65lb/ft)
Temperature Range: -60 to 80F
(Standard Formula Flammable) note.


TYPICAL PERFORMANCE OF C-RAM MMW-2 LIGHTWEIGHT FOAM
Design Note: (MT)
LOSSY, CARBON FILLED, FLEXIBLE FOAM

Thickness Frequency Reflectivity
0.125 70 110 GHz >17 dB
0.250 40 110 GHz >20 dB
0.500 26 110 GHz >20 dB

TYPICAL PHYSICAL PROPERTIES
Color: Black
Density (dependent upon grade): 0.06 to 0.13g/cm ( 4 to 8 lb/ft)
Service Temperature: -60F to 180F


TYPICAL PERFORMANCE OF C-RAM MMW-3 ELASTOMERIC
Design Note: (FLX)

Thickness Weight Frequency Reflectivity
0.040 (1 mm) .5 lb/ft

26 to 40 GHz -20dB
40 to 110 GHz >-15dB

TYPICAL PHYSICAL PROPERTIES
Color: Grey
Service Temperature: -80 to 275F (-62 to 134C)
Flammability: Non-Flammability

 

 

Typical Reflectivity

Frequency

LOSS. dB

MMW-1

 (0.25")

MMW-1

(0.5")

MMW-2

(0.125")

MMW-2

(0.25")

MMW-2

(0.5")

MMW-3

(0.4")

18 GHz

-

-

-

-

-

-

26 GHz

-

20

-

-

20

20

40 GHz

-

20

-

20

20

20

70 GHz

20

20

17

20

20

15

110 GHz

20

20

17

20

20

15

 

Cuming Flexible Jaumann Absorber Sheet Material

 

C-RAM LPJ

 Flexible Radar Absorber

C-RAM LPJ is a series of lightweight, flexible, weatherproof radar absorbers which can be used indoors, outdoors, or wherever the material may be in contact with water, oil, or other liquids.

C-RAM LPJ is made of alternating layers of closed-cell polyethylene foam and resistive layers. It is based on the Jaumann principle of operation.

C-RAM LPJ is designed to provide typically 18 dB of reflectivity reduction in a frequency range dependant on grade.

C-RAM LPJN is designed to provide typically 20 dB of reflectivity reduction in the frequency range
of 8-18 GHz.


2.5 GHz - 18 GHz

 

Cuming C-RAM LPJ Absorber 

 

Data 

LPJ

 

Data

LPJN

 

 

APPLICATIONS


The radar absorber is useful for reducing reflections from flat surfaces, columns, and structures such as bridges. Its easy-to-clean surfaces and non-dusting behavior make it suitable for cleanroom applications.

The standard size of C-RAM LPJ is 24 x 24 in. Standard thicknesses are noted in the chart below. Other thicknesses, shapes, and sizes are available on a custom order basis. It can be easily cut to special size or shape, and the edges do not require resealing. Sheets are bonded together or to a reflecting surface with a contact adhesive.

TYPICAL PROPERTIES


Color: White
Size: 24 x 24 standard
Service Temp.: -40F to +180F (LPJ)
-40F to +300F (RCJ)

 

TYPICAL PERFORMANCE OF LPJ

Grade
LPJ-373
LPJ-374
LPJ-375
LPJN
Frequency
8-18 GHz
6-12 GHz
2.5-8 GHZ
8-18 GHz
Reflectivity
-18 dB
-18 dB
-18 dB
-20 dB

 

 

Typical Reflectivity

Frequency

LOSS. dB

LPJ-373

 (0.45")

LPJ-374

(0.95")

LPJ-375

(1.3")

LPJN

(0.5")

2.5 GHz

-

-

18

-

6 GHz

-

18

18

-

8 GHz

18

18

18

20

12 GHz

18

18

-

20

18 GHz

18

-

-

20

 


 
  Last Updated: June 13, 2019
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An Electro Mechanical Research and Development (EMRAD) Corporation, Company
 
 

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