Dual-Band Frequency-Selective Absorptive Structure With Low Reflection

In this letter, a dual-polarized frequency-selective absorptive structure is presented with two wideband transmission windows. The transmission windows are achieved within a wide -10-dB reflection band. At the frequencies of the passbands, the out-of-phase currents are excited without flowing through the lossy elements. Therefore, the passbands can be obtained with high transmittance. Moreover, only four resistors are loaded on each unit cell to consume the out-of-band reflective wave. By combining lossy flower-shaped and lossless arrays together, the desired dual-band and low reflection performances can be realized. Within the operating band, the reflection is below -10 dB with the fractional bandwidth of 127%. Meanwhile, around 6.5 and 12 GHz, the passband widths are 39% and 40% and the corresponding insertion losses are 0.07 and 0.1 dB, respectively. Finally, the fabricated prototype is measured to demonstrate the feasibility of the presented method.