Design of an Inkjet-Printed Broadband Pixelated FSS Based Absorber Towards Unity Absorption

We present a thin planar pixelated frequency selective surface (FSS) based absorber engineered to achieve near unity absorption over a wide bandwidth. The absorber design for unity absorption in a planar configuration is highly challenging because it requires a crucial trade-off between bandwidth, thickness, and absorption level. We demonstrate a simple design strategy adopted to fulfill such steep constraints simultaneously. The unit cell consists of a simple FSS layer inkjet printed over a paper substrate, attached to a grounded foam substrate. We have achieved a wideband absorption of more than 99.999% by reducing the reflection level below −50 dB from 12.17 to 13.33 GHz for normally incident plane waves. The absorber also maintains the −10 dB bandwidth from 8.51 to 18.85 GHz. The absorber offers −10, −20, −30, −40, and −50 dB fractional bandwidths of 75.6%, 43.57%, 25.1%, 14.65%, and 9.1% respectively. The proposed absorber is suitable for conformal shield packaging.