2020-12-01
Resonance Based Discrimination of Stealth Targets Coated with Radar Absorbing Material (RAM)
By
Progress In Electromagnetics Research M, Vol. 99, 69-79, 2021
Abstract
For the first time, a real sized complex target that is coated with an absorber material is discriminated from the uncoated one using an aspect independent discrimination method based on natural resonances. This resonance based technique provides a real-time, accurate and aspect independent solution for stealth target discrimination. First, the discrimination is studied for a complex shaped aircraft of electrical size 1.5λ. The Perfectly Electrically Conducting (PEC) target is coated uniformly with sintered nickel-zinc-ferrite, a magnetic Radar Absorbing Material (RAM) with complex dielectric and magnetic properties. The resonant range Radar Cross Section (RCS) of the aircraft for different coating thicknesses is computed using the Method of Moments (MoM). The resonances contained in the RCS are extracted using the vector fitting method, and the dominant resonances representing the target are determined by applying the power criteria. The variation in the pole placements with the increasing coating thickness is also studied. A one number quantifier of discrimination --- ``Risk'' in dB is defined to express the amount of mismatch between the compared targets. Further, the discrimination technique is also studied for an aircraft of electrical length, 7λ. A Risk value of 2 dB and more is obtained in this study at all aspects. This demonstrates the capability of the algorithm to discriminate between targets of identical structure but with different material compositions.
Citation
Sathyamurthy Anuradha, and Jyothi Balakrishnan, "Resonance Based Discrimination of Stealth Targets Coated with Radar Absorbing Material (RAM)," Progress In Electromagnetics Research M, Vol. 99, 69-79, 2021.
doi:10.2528/PIERM20101001
References

1. Zaker, R. and A. Sadeghzadeh, "Passive techniques for target radar cross section reduction: A comprehensive review," International Journal of RF and Microwave Computer-Aided Engineering, Vol. 30, 2020, https://doi.org/10.1002/mmce.22411.
doi:10.1002/mmce.22411        Google Scholar

2. Sengupta, S., H. Council, D. R. Jackson, and D. Onofrei, "Active radar cross section reduction of an object using microstrip antennas," Radio Science, Vol. 55, 2020, https://doi.org/10.1029/2019RS006939.
doi:10.1029/2019RS006939        Google Scholar

3. Knott, E. F., J. F. Schaeffer, and M. T. Tuley, "Radar cross section," SciTech, 2004.        Google Scholar

4. Zikidis, K., A. Skondras, and C. Tokas, "Low observable principles, stealth aircraft and anti-stealth technologies," Journal of Computations & Modelling, Vol. 4, No. 1, 129-165, 2014, ISSN: 1792-7625 (print), 1792-8850 (online), Scienpress Ltd., 2014.        Google Scholar

5. Baum, C. E., E. J. Rothwell, Y. F. Chen, and D. P. Nyquist, "The singularity expansion method and its application to target identification," Proceedings of the IEEE, Vol. 79, No. 10, 1481-1492, Oct. 1991.
doi:10.1109/5.104223        Google Scholar

6. Anuradha, S. and J. Balakrishnan, "Discrimination of closely resembling PEC targets based on natural resonant frequencies," IEEE-MTT International Microwave And RF Conference (IMARC), Bengaluru, Dec. 2014.        Google Scholar

7. Anuradha, S. and J. Balakrishnan, "Resonance based discrimination of targets with minor structural variations," 2016 Asia-Pacific Microwave Conference (APMC), New Delhi, 2016.        Google Scholar

8. Anuradha, S. and J. Balakrishnan, "Radar target discrimination of real size aircraft with minor structural variations: Challenges and solutions," Progress In Electromagnetics Research C, Vol. 102, 139-148, 2020.
doi:10.2528/PIERC20031805        Google Scholar

9. Luiza de, C. F., M. A. Alves, and M. C. Rezende, "Microwave absorbing paints and sheets based on carbonyl iron and polyaniline: measurement and simulation of their properties," Journal of Aerospace Technology and Management, Vol. 2, No. 1, 63-70, 2010.
doi:10.5028/jatm.2010.02016370        Google Scholar

10. Rao, S. M., C.-C. Cha, R. L. Cravey, and D. L. Wilkes, "Electromagnetic scattering from arbitrary shaped conducting bodies coated with lossy materials of arbitrary thickness," IEEE Transactions on Antennas and Propagation, Vol. 39, 627-631, May 1991.
doi:10.1109/8.81490        Google Scholar

11. Analoui, M. and Y. Kagawa, "Electromagnetic scattering from conductor-coated material bodies," International Journal of Numerical Modelling: Electronic Networks, Devices and Fields, Vol. 4, No. 4, 287-299, 1991.
doi:10.1002/jnm.1660040404        Google Scholar

12. Howell, W. E. and H. Uberall, "Complex frequency poles of radar scattering from coated conducting spheres," IEEE Transactions on Antennas and Propagation, Vol. 32, No. 6, 624-627, Jun. 1984.
doi:10.1109/TAP.1984.1143382        Google Scholar

13. Vollmer, H. and E. J. Rothwell, "Resonance series representation of the early-time field scattered by a coated cylinder," IEEE Transactions on Antennas and Propagation, Vol. 52, No. 8, 2186-2190, Aug. 2004.
doi:10.1109/TAP.2004.832331        Google Scholar

14. Wierzba, J. F. and E. J. Rothwell, "E-pulse diagnostics of curved coated conductors with varying thickness and curvature," IEEE Transactions on Antennas and Propagation, Vol. 54, No. 9, 2672-2676, Sept. 2006.
doi:10.1109/TAP.2006.880786        Google Scholar

15. Rothwell, E. J. and G. D. Dester, "E-pulse diagnostics of a coated conductor using a nonplanar interrogation field," IEEE Transactions on Antennas and Propagation, Vol. 57, No. 2, 587-590, Feb. 2009.
doi:10.1109/TAP.2008.2011409        Google Scholar

16. Chantasen, N., A. Boonpoonga, and S. Burintramart, "Radar target identification of coated object using Cauchy method," IEEE Conference on Antenna Measurements & Applications (CAMA)-2015, 1-3, Chiang Mai, 2015.        Google Scholar

17. Chauveau, J., N. de Beaucoudrey, and J. Saillard, "Modification of resonance poles of a conducting target by a dielectric coating," 2007 European Radar Conference, 440-443, Munich, 2007.
doi:10.1109/EURAD.2007.4405032        Google Scholar

18. Gustavsen, B. and A. Semlyen, "Rational approximation of frequency domain responses by vector fitting," IEEE Trans. Power Delivery, Vol. 14, No. 3, 1052-1061, Jul. 1999.
doi:10.1109/61.772353        Google Scholar

19. FEKO Suite 7 User Manual, EM Software and Systems (EMSS), 2014.        Google Scholar

20. Raju, A. U., "Radar cross section (RCS) analysis of complex shaped radar absorbing material (RAM) coated bodies,", Bengaluru, May 2013 (Thesis).        Google Scholar

21. Kolanowska, A., D. Janas, A. P. Herman, R. G. Jerysiak, T. Gizwski, and S. Boncel, "From blackness to invisibility - Carbon nanotubes role in the attenuation of and shielding from radio waves for stealth technology," Carbon, Vol. 126, 31-52, 2018, ISSN 0008-6223, https://doi.org/10.1016/j.carbon.2017.09.078.
doi:10.1016/j.carbon.2017.09.078        Google Scholar