| 摘要 |
In one aspect, a multi-layer absorber is disclosed, which comprises a proximal layer having a radiation-receiving surface adapted for receiving electromagnetic radiation, and a distal layer disposed adjacent the proximal layer to receive at least a portion of the received radiation, if any, transmitted through said proximal layer, wherein said proximal layer exhibits an index of refraction having a real part that is less than the real part of an index of refraction of the said distal layer for at least one frequency of the electromagnetic radiation in a range of about 1 GHz to about 110 GHz. |
| 主权项 |
1. A multi-layer absorber, comprising
a polymeric proximal layer having a radiation-receiving surface for receiving electromagnetic radiation, and a polymeric distal layer disposed adjacent the proximal layer to receive at least a portion of the received radiation, if any, transmitted through said proximal layer, a plurality of radiation-absorbing additives distributed within at least one of said layers, said additives being capable of absorbing electromagnetic energy at one or more frequencies in a range of about 20 GHz to about 110 GHz, wherein said proximal layer exhibits an index of refraction having a real part that is less than the real part of an index of refraction of the said distal layer for at least one frequency of the electromagnetic radiation in said range of about 20 GHz to about 110 GHz, wherein the real parts of the indices of refraction of said layers at said at least one frequency satisfy the following relation:
1≦(nrd−nrp)f≦20, wherein,
nrd denotes the real part of the index of refraction of the distal layer,nrp denotes the real part of the index of refraction of the proximal layer, and f (in units of GHz) denotes the frequency at which the difference in real parts of the indices of refraction of the proximal and distal layers is determined, and wherein said multi-layered absorber exhibits a reflectance coefficient less than about 0.3 and a transmission coefficient less than about 0.3 for incident radiation in a frequency band within said frequency range of about 20 GHz to about 110 GHz. |
