Metamaterial-reflective half-wave plate

Cardiff University's magnetic mirror half-wave plate design for b-mode polarisation modulation across wide bandwidths. Less than 1 mm thick, this metamaterial-based design employs a combination of a grid-based 'artificial magnetic conductor' and metal 'perfect electrical conductor' surfaces. The overall effect is to create a differential phase-shift between orthogonal polarisations equal to 180 degrees. The rotation of the plate causes modulation of the polarisation signal.