Artificial dielectric devices for variable polarization compensation at millimeter and submillimeter wavelengths

Variable polarization compensation has been demonstrated at 100 GHz. The device consists of two interlocking V-groove artificial dielectric gratings that produce a birefringence that varies with the separation distance. A maximum retardance of 74 [degrees] has been obtained experimentally in a silicon device, in good agreement with rigorous coupled-wave computer simulations. Further simulations predict that adding quarter wave dielectric antireflection (AR) coatings to the outer surfaces of the device can reduce the insertion loss to below 4 dB. The use of rectangular grooved gratings provides increased retardance and reduced loss. It is predicted that a coupled device with a rectangular grooved gratings will be capable of maximum retardance in excess of 180[degrees], with low insertion loss ( Index Terms--Anisotropic media, birefringence, compensation, micromachining, microwave measurements, millimeter wave devices, polarization, submillimeter wave devices.