David R Downen

US Patent:

41624963, Jul 24, 1979

Filed:

Apr 3, 1967

Appl. No.:

4/628170

Inventors:

David N. Downen - Tulsa OK
Bert A. Eichenberger - Panorama City CA

Assignee:

Rockwell International Corporation - El Segundo CA

International Classification:

H01Q 1700

US Classification:

343 18A

Abstract:

A radar attenuator panel incorporating reactive elements is provided comprising a composite of electrically semiconductive or reactive layers separated by relatively non-conductive layers with the entire structure bonded together with compatible thremosetting resins. The electrically reactive attenuator layers have a complex admittance wherein the imaginary portion is substantial compared with the real portion. A sheet having a ratio of the imaginary portion to the real portion of complex admittance in the range of 0. 7 to 2. 0 throughout the frequency range from S-Band through X-Band is provided by impregnating a glass fabric with a phenolic resin having amorphous carbon and aluminum particles dispersed therein. The carbon is preferably present in the range of 9 to 18 parts by weight and the aluminum is preferably present in the range of 5 to 42 parts by weight per 60 parts by weight of resin. The reactive layers are separated by a cellular honeycomb relatively low dielectric material that may be free of semi-conductive particles to obtain a controlled space between the reactive sheets.