Ultra-wideband RCS Reduction Using Checkerboard Configuration of Bed of Nails

Artificial magnetic conductors (AMCs) have the characteristics of reflection phase variation with frequency. This feature can be used to reduce the radar cross-section (RCS) of ground planes when the checkerboard arrangement of different AMCs is applied. Scattered fields of checkerboard surface are re-directed in four directions and cause a wide frequency range of 10-dB RCS reduction. This paper proposes a novel ultra-wideband structure to reduce RCS using a bed of nails as AMC. AMCs of the proposed structure have the same shape but different dimensions. Initially, the cylindrical form of a bed of nails is designed, and the results show the RCS reduction is less than −10dB over the frequency range of 6.78 – 18. 24 GHz, which is 91.6 %. This range is the same as the predicted one using array theory with a good approximation. Then the rectangular and conical form of a bed of nails is applied. For rectangular form, the RCS reduced more than 10 dB in the frequency range of 6.9 – 18.1 GHz, equivalent to 89.6 %, and is less than cylindrical form. The simulated results of the conical form show 93.3% (6.6 – 18.15 GHz) bandwidth which is wider than cylindrical form.