CVD Diamond:
Dielectric Properties

CVD diamond exhibits remarkable dielectric properties including a low dielectric constant of 5.7, a loss tangent below 0.00005 at 145GHz and a high dielectric strength of 1 000 000 V/cm. In combination with the extremely high thermal conductivity, low thermal expansion coefficient and high mechanical strength CVD diamond is an ideal dielectric window material. In particular for high-power microwave tubes (Gyrotron) with power levels exceedings 1 MW edge cooled diamond windows have found tremendous interest. 

Mapping of the dielectric losses (FZK, Karlsruhe)