Low-Cost Metamaterial Absorbers for Sub-GHz Wireless Systems

The possibility of realizing low-cost ultra-thin and angularly stable absorbers at low frequencies is investigated. It is demonstrated that ultra-thin absorbers comprising metallic high impedance surfaces can be realized by using a low-cost fabrication process. This approach opens up the realistic possibility of employing such absorbing panels to improve the performance of wireless systems operating in complex environments (e.g., radio frequency identification systems). The substrate here employed is a common cardboard panel, and the metallized parts are realized through a conventional aluminum foil or by using a commercial spray paint used for shielding. Experimental tests are provided both in a waveguide environment at 5 GHz and in free space at 868 MHz.