Silicon nanomembrane based photonic crystal waveguide array for wavelength-tunable true-time-delay lines Appl. Phys. Lett. 101, 051101 (2012) Cryogenic single-shot spectroscopy of a floating poly-silicon gate transistor J. Appl. Phys. 112, 014510 (2012) Microwaves in dispersive magnetic composite media (Review Article) Low Temp. Phys. 38, 603 (2012) Experimental realization of a broadband conformal mapping lens for directional emission Appl. Phys. Lett. 100, 261907 (2012) Additional information on J. Appl. Phys. A metamaterial surface formed by three slot gratings at 60 to each other has two possible highsymmetry arrangements. One forms equilateral triangular metal patches, the other a combination of hexagons and small equilateral triangles. When spaced above a ground plane with a thin dielectric spacer both structures give strong microwave absorption at certain resonant frequencies, which is largely angle independent. The results of microwave reflectivity measurements are here presented for the two distinct sample geometries and compared with predictions from finite element method models. V C 2012 American Institute of Physics. [http://dx