Pyramidal lightweight radio absorbers

ECCOSORB VHP provides the highest broad band performance at both normal incidence and at wide incidence angles of all known absorbers. While primarily designed for low forward scatter, it offers favorable back scatter properties as well. It is thus well suited for use in all regions of anechoic chambers. Since it is available in a variety of thicknesses, the chamber designer has the opportunity to choose versions appropriate for specific requirements. The versions indicated in the table (over) are offered. The standard absorber colors is light blue. Standard sheet size is 61cm x 61cm (24in x 24in) With regard to physical characteristics, ECCOSORB VHP is in the form of an array of sharp pointed pyramids made of carbon impregnated urethane foam. As a result it is light weight, flexible and tolerant of physical abuse.

The recommended mounting is chloroprene adhesion. ECCOSORB VHP is also available at slight additional cost with Velcro zippers for ease of attachment and removal. ECCOSORB VHP products conform to non-flammability requirements of ASTM D-1692- 74. Improved processing procedures make it possible to offer ECCOSORB VHP to meet all requirements of Test 1 and 2 of NRL Report No.8093, and in addition, to meet most of the toxic-gas limits set by this report.

This information is not to be taken as warranty or representation for which we assume legal responsibility, nor as permission or recommendation to practice any patented invention without licenses. It is offered solely for consideration, investigation, and verification.

Absorption performance of ECCOSORB VHP in angle near normal incidence

Reflection Coefficient vs angle of incidence of ECCOSORB VHP

Note: Every piece is measured to establish compliance with the nominal minimum performance given in the table above. Also note this test was performed in the case of metal back.

Pyramidal broadband absorber for millimeter wave range

The EC-SORB ECP-3 is pyramidal absorber which is intended to have high performance at especially millimeter wave range. Basically, pyramidal absorber has high performance at very wide frequency range. Such as the absorption characteristics is increasing with 6dB/oct. slant at low frequency range. Increasing frequency, and the number (Ｄ/λ) which the height of pyramid divided by the wave length λ is almost reaching 3 to 4, the performance reaches to 50dB and maintains such 50dB at higher frequency. By the pyramidal absorber’s basic frequency characteristics, the performance is maintained to 50dB at high frequency range but cannot maintain the performance at infinite higher frequency.

Please watch the figure-2, it shows absorption performance of ordinary 3in pyramid and ECP-3.

The EC-SORB ECP-3 which is developed for millimeter wave shows very good high performance even 110 GHz high frequency but the ordinary 3in absorbers performance is on down ward trend at the frequency.

ECP-3 has basic good characteristics of pyramidal absorbers such as low forward and back scatter. So, EPC-3 should work well in anechoic chambers such as radar test range.

In terms of physical properties, EC-SORB ECP-3 is made of urethane as a base material and pyramids containing electrical conductive carbon is lining up. For that reason, ECSORB ECP-3 is lightweight, flexible and it has high durability. By using a Velcro zipper, detachment can be done easily.

EC-SORB ECP-3 meets the flame retardancy requirement of UL standard 94 HBF.

Absorption performance of EC-SORB ECP in angle near normal incidence

Reflection Coefficient vs angle of incidence of EC-SORB ECP

This information is not to be taken as warranty or representation for which we assume legal responsibility, nor as permission or recommendation to practice any patented invention without licenses. It is offered solely for consideration, investigation, and verification.

This information is not to be taken as warranty or representation for which we assume legal responsibility, nor as permission or recommendation to practice any patented invention without licenses. It is offered solely for consideration, investigation, and verification.

Flexible & Thin-type radio absorbers

ECCOSORB AN is a light weight flexible foam sheet broadband microwave absorber. It can be readily cemented to or draped over items which produce undesired reflection.

Representative use
Examples are radar antenna nacelles, anechoic enclosures, antenna or target test mounts in radar ranges, etc.

Reflectance factor
By appropriate choice of design type, less than 1% reflection for normally incident energy can be obtained over several frequency bands ranging from 0.6 to 50 GHz (se performance table and curves on next page). ECCOSORB AN is equally effective against linear, elliptical or circular polarization. It is relatively insensitive to changes in incidence angle; for example, the reflectivity of ECCOSORB AN75 at 70°incidence, at parallel polarization, at 9.5 GHz has been measured at 17 dB below a metal plate.

Reflection of visible light and infrared
Typical infrared reflectance ranges from 0.1% at 1 micron to 6% at 40 microns for any surface color. Visible light reflectance is 0.1% when colored black; standard ECCOSORB AN is light blue surfaced to improve light reflection, while not appreciably affecting infrared reflectance.

Handling procedure
Installation is straightforward. ECCOSORB AN can cut to appropriate shape with scissors or a sharp knife; a household electric knife has been found to be especially effective. It can be formed easily to compound curves. It may be attached to either metallic surfaces or non-metallic surfaces. Metallic surface is preferred for rated electrical performance of the absorber. However, it is permissible to use non-metallic mounting surfaces or no backing at all still achieve adequate reflectivity characteristics.

Installation
Many techniques are possible for permanent attachment to surfaces.
After chloroprene adhesive sprayed or brushed on both surfaces, leave it for a few minutes to 10 minutes, then press installation surface.
They can also be used to join edges of absorber to form a continuous blanket.
The amount of adhesive required absorber per sheet varies widely, depending on working methods, please refer to the quantity as below.

With 1 gallon chloroprene adhesive
1) With spray: 15~20pcs
2) With brushe:10~12pcs
3) For vertical and overhead installations, nails or small serrated pins attachment surface have been used successfully.
4) If you need to be able to instantly attach and detach the absorber, put a velcro zipper the back of absorber with chloroprene adhesive.

Environmental condition
1) Performance is not impaired by exposure to high relative humidity.
2) Useful temperature range is from -50℃（-58°F）to +120℃（248°F）.
3) For continuous use -20℃（-4°F）to +80℃（176°F）.
4) In situations where the absorber will be in contact with water, fuel, or hydraulic fluids and for outdoor exposure, ECCOSORB AN-W or ECCOSORB AN-P is recommended.

Feature size
ECCOSORB AN can be furnished to special order in any size desired.
Standard sheet size is 61cm x 61cm (24in x 24in).

Note This information is not to be taken as warranty or representation for which we assume legal responsibility, nor as permission or recommendation to practice any patented invention without licenses.
It is offered solely for consideration, investigation, and verification.

Performance Table