A frequency tunable multi-layer low cost microwave absorber is proposed for Ku and X bands of applications. The tunability is obtained with the cavity model design using two metallic layers; a frequency selective surface (FSS) layer and a metal backed substrate layer with the air gap between them. The change in air-gap results in variation of the effective substrate height, and as a consequences the resonant frequency is tuned. The coupling of LC resonance and cavity resonance at an air-gap of 7.5 mm results in a dual-band absorption of the design. The proposed absorber performance has been analyzed for both TE and TM polarizations of incident wave, and the results are found to be same. The studies on surface current distribution and incident angle variation are observed to get physical insight behind absorption. The waveguide measurement method is used to correlate the simulated results with the measured one. With this simple cost efficient design, the absorber appears well suited for EMI/ EMC application at X and Ku bands.
2. Rufangura, P. and C. Sabah, "Polarisation insensitive tunable metamaterial perfect absorber for solar cells applications," IET Optoelectronics, Vol. 10, No. 6, 12, 2016.
doi:10.1049/iet-opt.2016.0003
3. Grant, J., et al., "Polarization-insensitive terahertz metamaterial absorber," Opt. Lett., Vol. 36, No. 8, April 2011.
4. Zhu, W. and X. Zhao, "Metamaterial absorber with dendritic cells at infrared frequencies," J. Opt. Soc. Amer. B, Vol. 26, No. 26, 2382-2385, December 2009.
doi:10.1364/JOSAB.26.002382
5. Gong, Y., et al., "Highly flexible all-optical metamaterial absorption switching assisted by Kerrnonlinear effect," Opt. Express, Vol. 19, No. 11, 10193-10198, 2011.
doi:10.1364/OE.19.010193
6. Zhai, H., et al., "A new tunable dual-band metamaterial absorber with wide-angle TE and TM polarization stability," Journal of Electromagnetic Waves and Applications, Vol. 29, No. 6, 774-785, 2015.
doi:10.1080/09205071.2015.1024335
7. Wang, B. X., L. L. Wang, G. Z. Wang, W. Q. Huang, X. F. Li, and X. Zhai, "Frequency continuous tunable terahertz metamaterial absorber," J. Lighwave Technol., Vol. 32, 1183-1189, 2014.
doi:10.1109/JLT.2014.2300094
8. Zhao, J., Q. Cheng, J. Chen, M. Q. Qi, W. X. Jiang, and T. J. Cui, "A tunable metamaterial absorber using varactor diodes," New J. Phys., Vol. 15, 043049, 2013.
doi:10.1088/1367-2630/15/4/043049
9. Lin, B. Q., S. H. Zhao, W. Wei, X. Y. Da, Q. R. Zheng, H. Y. Zhang, and M. Zhu, "Design of a tunable frequency selective surface absorber as a loaded receiving antenna array," Chin. Phys. B, Vol. 23, 024201, 2014.
doi:10.1088/1674-1056/23/2/024201
10. Zheng, H. Y., X. R. Jin, J. W. Park, Y. H. Lu, J. Y. Rhee, W. H. Jang, H. Cheong, and Y. P. Lee, "Tunable dual-band perfect absorbers based on extraordinary optical transmission and Fabry-Perot cavity resonance," Opt. Express, Vol. 20, 24002-24009, 2012.
doi:10.1364/OE.20.024002
11. Chen, J., Z. Hu, G. Wang, X. Huang, S. Wang, X. Hu, and M. Liu, "High-impedance surface-based broadband absorbers with interference theory," IEEE Transactions on Antennas and Propagation, Vol. 63, No. 10, 4367-4374, October 2015.
doi:10.1109/TAP.2015.2459138
12. Collin, R. E., Foundations for Microwave Engineering, 2nd Ed., 501, Wiley-IEEE Press, January 2001.
doi:10.1109/9780470544662
13. Zhai, H., C. Zhan, L. Liu, and Y. Zang, "Reconfigurable wideband metamaterial absorber with wide angle and polarization stability," Electronics Letters, Vol. 51, No. 21, 1624-1626, October 8, 2015.
doi:10.1049/el.2015.1557
14. You, J. W., J. F. Zhang, W. X. Jiang, H. F. Ma, W. Z. Cui, and T. J. Cui, "Accurate analysis of finite-volume lumped elements in metamaterial absorber design," IEEE Transactions on Microwave Theory and Techniques, Vol. 64, No. 7, 1966-1975, July 2016.
doi:10.1109/TMTT.2016.2572180
15. Li, L., Y. Yang, and C. H. Liang, "A wide-angle polarization insensitive ultra-thin metamaterial absorber with three resonant modes," J. Appl. Phys., Vol. 110, 063702, 2011.
doi:10.1063/1.3638118
Submit
