Interference type radiation attenuator
AssigneeRockwell International Corporation
InventorsDonald D. Haley, Louis Maus
Life of this patent
Estimating the term…
Abstract
An attenuator of electromagnetic radiation, such as radar, is described wherein a single attenuator sheet in the nature of "spacecloth" is placed in front of a plurality of reflective layers wherein each of the reflective layers is tuned to reflect a narrow band of radiation of a selected frequency and transmit other frequencies; and each of the reflective layers is spaced from the attenuation layer at a distance of one-fourth of the wavelength of electromagnetic radiation to which it is tuned. In a preferred embodiment each of the reflective layers comprises elongated narrow conductive areas arranged in spaced apart columns and rows in a generally non-conductive area.
Claims16
An attenuator of electromagnetic radiation comprising:
- an impedance layer having a uniform impedance which is substantially the same impedance as free space, said radiation passing through said layer;
- and
- a reflective and transparent layer tuned to reflect a selected frequency of electromagnetic radiation and transmit other frequencies, said reflective and transparent layer being spaced from said impedance layer at a distance of one fourth of the wavelength of electromagnetic radiation of the selected frequency.
A broad band radiation attenuator comprising a plurality of mutually spaced layers including:
- a first layer having an impedance substantially the same as the impedance of the medium through which radiation is propagated to the attenuator;
- a second layer having an impedance for reflecting incident radiation;
- and
- at least a third layer interposed between the first and second layers and having an impedance tuned to reflect a selected frequency of radiation and to transmit radiation of frequencies adjacent said selected frequency, said third layer being spaced from said first layer at a distance of one-fourth of said selected frequency;
- and
- said second layer being spaced from said first layer at a distance of one-fourth of a frequency reflected thereby.
A broad band attenuator of electromagnetic radiation of radar frequencies comprising:
- means for absorbing radiation from the electric field of electromagnetic radiation;
- first means for reflecting electromagnetic radiation of a first frequency and transmitting radiation of a second frequency, said first means for reflecting being spaced from said means for absorbing at an effective distance of one fourth of the wavelength of the first frequency;
- second means for reflecting electromagnetic radiation of the second frequency and transmitting radiation of other frequencies, said second means for reflecting being spaced from said means for absorbing at an effective distance of one fourth of the wavelength of the second frequency, whereby said means for absorbing can attenuate radiation of the first frequency and of the second frequency.
Dependencies are inferred from the claim text.