Reducing reflection of bandpass frequency selective surface using checkerboard surface

A hybrid structure with the properties of low-frequency transmission and reflection reduction at high frequencies is designed and demonstrated experimentally. The bandpass frequency selective surface (FSS) working at low frequencies is firstly proposed. Then, the checkerboard surface that can scatter the reflected electromagnetic (EM) wave is also introduced on the top layer. The two layers are separated by a foam spacer to gain the hybrid structure. Due to the metal-like reflection behavior of the FSS at high frequencies, integrating with the checkerboard surface results in low reflection in a broad frequency band, while the efficient transmission at low frequencies can be achieved all the same. Simulated results show that the proposed hybrid structure can achieve a reflection reduction of more than 10 dB in the frequency range of 8.4-18 GHz, as well as the transmission coefficient greater than -1 dB from 3.7 to 4.3 GHz. Finally, the experimental measurement has also been performed to provide a good demonstration. The proposed results can be seen as a good candidate in the applications of stealth techniques, EM compatibility and so on.