A broadband flexible metamaterial absorber with a transparent window

A novel, broadband flexible metamaterial absorber is designed. The absorber is consisted of loaded high-impedance surfaces (HIS) on a flexible polyethylene terephthalate (PET) substrate and the back-metal layer replaced with a polarization-insensitive frequency-selective surface separated by a dielectric layer. The proposed absorber can obtain the bandwidth with the reflectivity below -10 dB in the frequency range of 7-16 GHz with a transparent window at 2.9 GHz. Losses in the high-impedance surface are introduced by printing the periodic pattern through resistive inks and hence avoiding the typical soldering of lumped resistors.