RA Mayes | Cuming Microwave Corp | Flat Foam Microwave and Radar Absorber

Flexible Foam Microwave Absorber

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Model

Features

Layered Foam 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

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-WP is standard LF absorber which has been spray coated with a thin film of polyurethane elastomer, which provides a waterproof barrier. This is the preferred version for protecting complex shapes.

Standard product size for all grades of LF and LF-W is a flat panel 610 x 610 mm (24 x 24 in.). Other dimensions are possible, including larger parts formed by butt-joining sections together.

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

Reticulated Foam Microwave Absorber

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Model

Features

C-RAM AR

SP - Standard Performance

HP - High Performance

RETICULATED FOAM BROADBAND
RADAR ABSORBER
2 GHz - 100 GHz

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

Lossy, Carbon Filled, Flexible Flat Foam Microwave Absorber

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Model

Features

C-RAM MT

1/4" to 4.0" High x

24" x 24" (610 x 610 mm)
CARBON FILLED

FLEXIBLE FOAM SHEET

1 GHz - 100 GHz

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

GRADE

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 anyreflections at interfaces. It is independent of thickness. This is a calculated, not measured, value.