Abstract: Apparatuses such as inserts for radomes are described herein. The apparatuses and inserts including a metal layer having a frequency selective surface.

Abstract: A secondary heat shield is positioned within a heat shielding radome and spaced from the nose of the radome in order to protect an antenna against thermal radiation from the inner surface of the radome. The secondary heat shield can be a single unitary component integrally formed of a lightweight ceramic which can be easily fabricated in the desired shape and which maintains its shape. The secondary heat shield can be formed of a lightweight ceramic material having a dielectric constant at 17 GHz and 21.degree. C. in the range of about 1 to about 3.5, a thermal conductivity of less than 0.7 W/M-K, and a density at 21.degree. C. of less than 3.2 g/cc. The most preferred ceramic material has a dielectric constant at 17 GHz and 21.degree. C. in the range of about 1.01 to about 2.0, a thermal conductivity in the range of about 0.04 to about 0.08 W/M-K, and a density at 21.degree. C. of less than about 1.0 g/cc.