To improve absorbing properties of phase-modulated surface (PMS), the multi-active-layer PMS composed of multiple active frequency-selective surface (AFSS) layers and one background plane is theoretically studied using time-modulation theory in this paper. The optimization of PMS's switching scheme using differential evolution (DE) algorithm is also proposed for minimizing scattering echo energy at the incident frequency. We provide analytical formulation for the scattering problem and obtain the angular scattering pattern of PMS after optimization. Simulation results indicate that the optimized switching scheme is beneficial for reducing the spatial coverage of scattering echo at incident frequency. This coverage can be further confined by the increasing number of active layers in PMS. Furthermore, it is shown that floor effect appears when the number of active layers reaches a certain value, which limits the PMS structure conversely.
1. Nair, R. U. and R. M. Jha, "Broadbanding of A-sandwich radome using Jerusalem cross frequency selective surface," CMC: Computers, Materials & Continua, Vol. 37, No. 2, 109-121, 2013.
2. Sazegar, M., et al., "Beam steering transmitarray using tunable frequency selective surface with integrated ferroelectric varactors," IEEE Transactions on Antennas and Propagation, Vol. 60, No. 12, 5690-5699, 2012. doi:10.1109/TAP.2012.2213057
3. Wu, P., et al., "Use of frequency-selective surface for suppressing radio-frequency interference from wireless charging pads," IEEE Transactions on Industrial Electronics, Vol. 61, No. 8, 3969-3977, 2014. doi:10.1109/TIE.2013.2284136
4. Tennant, A. and B. Chambers, "A single-layer tunable microwave absorber using an active FSS," IEEE Microwave and Wireless Components Letters, Vol. 14, No. 1, 46-47, 2004. doi:10.1109/LMWC.2003.820639
5. Chambers, B. and A. Tennant, "The phase-switched screen," IEEE Antennas and Propagation Magazine, Vol. 46, No. 6, 23-37, 2004. doi:10.1109/MAP.2004.1396733
6. Chambers, B. and A. Tennant, "A smart radar absorber based on the phase-switched screen," IEEE Transactions on Antennas and Propagation, Vol. 53, No. 1, 394-403, 2005. doi:10.1109/TAP.2004.838795
7. Tennant, A. and B. Chambers, "Experimental performance of a phase-switched screen against modulated microwave signals," IEE Proceedings-Radar, Sonar and Navigation, Vol. 152, No. 1, 29-33, 2005. doi:10.1049/ip-rsn:20041191
8. Chambers, B. and A. Tennant, "FDTD modelling of active radar absorbers," IEEE Antennas and Propagation Society International Symposium, 6027-6030, 2007.
9. Tennant, A. and B. Chambers, "Time-switched array analysis of phase-switched screens," IEEE Transactions on Antennas and Propagation, Vol. 57, No. 3, 808-812, 2009. doi:10.1109/TAP.2009.2013448
10. Chambers, B. and A. Tennant, "Reflectivity null tuning in multi-layer phase-switched active radar absorbers," IEE Proceedings-Radar, Sonar and Navigation, Vol. 152, No. 4, 245-247, 2005. doi:10.1049/ip-rsn:20050014
11. Tennant, A. and B. Chambers, "Experimental two-layer adaptive phase-switched screen," Electronics Letters, Vol. 37, No. 23, 1379-1380, 2001. doi:10.1049/el:20010952
12. Xu, W., et al., "An ultra-thin broadband active frequency selective surface absorber for ultrahigh-frequency applications," Journal of Applied Physics, Vol. 118, No. 18, 184903, 2015. doi:10.1063/1.4934683
13. Tennant, A. and B. Chambers, "RCS reduction of spiral patch antenna using a PSS boundary," IEE Proceedings-Radar, Sonar and Navigation, Vol. 152, No. 4, 248-252, 2005. doi:10.1049/ip-rsn:20045048
14. Tennant, A. and B. Chambers, "SSB-type frequency scattering from a single-layer PSS with interlaced element modulation," IEEE Antennas and Wireless Propagation Letters, Vol. 5, No. 1, 284-285, 2006. doi:10.1109/LAWP.2006.876968
15. Tennant, A. and B. Chambers, "In-phase and quadrature modulated scatterer," Electronics Letters, Vol. 38, No. 11, 498-499, 2002. doi:10.1049/el:20020349
16. Chambers, B., A. Tennant, and A. Melnikov, "Detection of a radar signal reflected from a phase-modulated surface," IEE Proceedings-Radar, Sonar and Navigation, Vol. 153, No. 4, 316-324, 2006. doi:10.1049/ip-rsn:20060010