Patent ID: 8314621

Claim:
A unit cell of a narrow band filter, the unit cell comprising: a matrix body having a first permittivity; an inclusion body disposed in the matrix body, the inclusion body having a second permittivity, wherein the matrix body and the inclusion body are configured to reflect electromagnetic radiation incident on an electromagnetic radiation facing surface of the matrix body and an electromagnetic radiation facing surface of the inclusion body, wherein a bandwidth of the reflected electromagnetic radiation is based on a difference between the first permittivity and a third permittivity, the third permittivity being an average permittivity between the first permittivity and the second permittivity based on a volume of the inclusion body and a volume of a portion of the matrix body, the portion of the matrix body being adjacent to and/or opposite the electromagnetic radiation facing surface of the inclusion body, and wherein the inclusion body is configured such that the second permittivity is adjustable to adjust the third permittivity, thereby adjusting the difference between the first permittivity and the third permittivity.