In this article, a broadband radar cross section (RCS) reduction metasurface with a reconfigurable high-selectivity passband is proposed. Based on the equivalent circuit analysis, the feasibility of achieving the high-selective passband with multimode working state and RCS reduction near the passband through the combination of the checkerboard metasurface and the switchable bandpass frequency selective structure (FSS) is verified. The switchable FSS in the bottom layer can realize the function of wave transmittance/reflection by controlling the on/off states of the p-i-n-diodes, and a novel staggered patch structure is introduced to realize the fast conversion between different working modes without using complex feeding networks. The checkerboard metasurface in the upper layer not only realizes the RCS reduction function through scattering cancellation but also improves the passband selectivity of the switchable FSS under different working modes. Finally, a prototype of the proposed structure is fabricated and measured. The measured results show that the proposed structure can be flexibly switched between the three working modes. In different working modes, the structure has a wide RCS reduction bandwidth and a high-selective passband.

This letter presents a frequency selective absorber (FSR) with a passband and two wide absorption bands. The structure is composed of a resistive layer and a bandpass frequency selective surface (FSS) layer. The resistive layer is a combination of metal lines with loaded resistors and rectangular spiral resonators, which generate parallel resonances. Square slots are designed in the bandpass FSS to produce parallel resonance inside the passband and perform as a metal plane outside the passband. A nearly transparent window can be obtained by adjusting the parallel resonant frequencies of two layers to be consistent. The simulation results show that the 3 dB transmission band ranges from 6.5 to 7.76 GHz, and the minimum insertion loss is 0.05 dB at 7.09 GHz. The dual-polarized FSR presents stable operating characteristics and realizes two absorption bands on both sides of the passband, and the fractional bandwidth of the reflection coefficient lower than −10 dB is up to 127%, which ranges from 2.69 to 12.04 GHz. In addition, the FSR is manufactured and measured, and the measurement results are consistent with the simulation results.

The integration of multiband transmission channels with broadband radar cross-section (RCS) reduction is a pivotal yet challenging goal for advanced stealth radomes. This paper proposes a frequency-selective binary metasurface (FSBM) that synergizes a binary coding metasurface with a frequency-selective surface (FSS) to simultaneously achieve high-selectivity dual-passband transmission and wideband RCS suppression. The top-layer binary metasurface, composed of two artificial magnetic conductors (AMC) units arranged in an optimized sequence, facilitates destructive interference for broadband backscattering suppression. The bottom-layer FSS, functioning as a second-order dual-band filter with aperture-coupled resonators, provides the desired passbands and acts as a near-perfect electric conductor (PEC) reflector in the stopband to enable AMC operation. A prototype is fabricated and measured, demonstrating two transmission bands at 5.14 GHz and 7.61 GHz with low insertion loss (IL) and steep roll-off, alongside a fractional bandwidth exceeding 76.3% for −10 dB RCS reduction. This work presents a viable path forward for developing low-scattering platforms for multiband radar and communication systems.