Lightweight, Ultra-Wideband, and Polarization-Insensitive Metamaterial Absorber Using a Multilayer Dielectric Structure for C- and X-Band Applications

The design of a lightweight and ultra-wideband absorber for C and X bands is still a challenge as the dimension of the absorber is relatively large in such a relatively low-frequency band. Herein, an ultra-wideband and lightweight metamaterial absorber (MMA) is presented for C- and X-band applications. The unit cell of the proposed MMA consists of four copper sectors loaded by lumped resistors and a continuous copper ground plane, which is printed on two FR-4 substrates. Furthermore, an airgap separating the FR-4 layers is used as the active substrate medium of the MMA to achieve both ultra-wideband absorption spectra and lightweight design. The MMA is investigated by simulation and measurement, showing that a good agreement is achieved. The result indicates that the absorptivity of the MMA under both transverse electric (TE) and transverse magnetic (TM) polarizations is greater than 90% in a wide range from 3.7 to 13.6 GHz for all polarization angles. Compared to other reported broadband absorbers, the proposed MMA shows an ultra-wide absorption bandwidth and a lightweight design, which demonstrates a great potential for C-and X-band applications.