Broadening bandwidth of the composite radar absorption material involving a frequency selective surface

Abstract

The design and fabrication of a composite ultrathin magnetic-type radar absorption material (RAM) exhibiting excellent properties of wide bandwidth is demonstrated in this study. RAMs with the range of 2–18 GHz are obtained based on EW (a type of iron carbonyl powder produced by BASF chemical company)-filled silicon rubber, into which an frequency selective surface (FSS) in the form of treble-square loops is embedded. The FSSs contribute to broadening bandwidth of the RAM without almost increasing the thickness. By designing the appropriate unit dimensions of FSS, an optimized operating bandwidth can be obtained. Experimental results are obtained and compared with simulation results in High Frequency Structure Simulator, and they demonstrated that the RAMs embedded with FSSs or resistive FSSs all have good results of broadening the effective frequency band, showing that the proposed RAM can provide a 10-dB reflectivity over the frequency range of 6.8–18 and 3.6–4.4 GHz, which is equivalent to a relative bandwidth of 92.2%; in addition, it also provide a 8-dB reflectivity reduction over the frequency range of 4.4–6.8 GHz. Furthermore, the total thickness of the proposed composite structure is less than 2 mm. A good match between simulated and measured results demonstrates the validity of our design.

Keywords:

• radar absorption material
• treble-square loops
• frequency selective surface simulation

Additional information

Funding

Funding. The authors gratefully acknowledge financial support of the Natural Science Foundation of Hubei Province, China [grant number ZRY0124] and the National Natural Science Foundation of China [grant number 61172003].