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Monostatic RCS Reduction by Gap-Fill with Epoxy/MWCNT in Groove Pattern

  • Choi, Won-Ho (Dept. of Aerospace Engineering, Korea Advanced Institute of Science and Technology) ;
  • Jang, Hong-Kyu (Dept. of Aerospace Engineering, Korea Advanced Institute of Science and Technology) ;
  • Shin, Jae-Hwan (Dept. of Aerospace Engineering, Korea Advanced Institute of Science and Technology) ;
  • Song, Tae-Hoon (Dept. of Aerospace Engineering, Korea Advanced Institute of Science and Technology) ;
  • Kim, Jin-Kyu (Dept. of Aerospace Engineering, Korea Advanced Institute of Science and Technology) ;
  • Kim, Chun-Gon (Dept. of Aerospace Engineering, Korea Advanced Institute of Science and Technology)
  • Received : 2011.09.22
  • Accepted : 2012.02.02
  • Published : 2012.03.31

Abstract

In this study, we investigated the effect of groove pattern and gap-fill with lossy materials at 15 GHz frequency of Ku-band. We used Epoxy/MWCNT composite materials as gap-fill materials. Although epoxy does not have an absorbance capability, epoxy added conductive fillers, which are multi-walled carbon nanotubes (MWCNT), can function as radar absorbing material. Specimens were fabricated with different MWCNT mass fractions (0, 0.5, 1.0, 2.0 wt%) and their permittivity in the Ku-band was measured using the waveguide technique. We investigated the effect of gap-fill on monostatic RCS by calculating RCS with and without gap-fill. For arbitrarily chosen thickness and experimentally obtained relative permittivity, we chose the relative permittivity of MWCNT at 2 wt% (${\varepsilon}_r$=8.8-j2.4), which was the lowest reflection coefficient for given thickness of 3.3 mm at V-pol. and $80^{\circ}$ incident angle. We also checked the monostatic RCS and the field intensity inside the groove channel. In the case of H-pol, gap-fill was not affected by the monostatic RCS and magnitude was similar with or without gap-fill. However, in the case of V-pol, gap-fill effectively reduced the monostatic RCS. The field intensity inside the groove channel reveals that different RCS behaviors depend on the wave polarizations.

Keywords

Radar Cross Section (RCS);Groove Pattern;Polarization;Scattering;Composite Material

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