Multifrequency superscattering is a phenomenon in which the scattering cross section from a subwavelength object simultaneously exceeds the single-channel limit at multiple frequency regimes.Here,we achieve simultaneo...Multifrequency superscattering is a phenomenon in which the scattering cross section from a subwavelength object simultaneously exceeds the single-channel limit at multiple frequency regimes.Here,we achieve simultaneously,within a graphene-coated subwavelength structure,multifrequency superscattering and superscattering shaping with different engineered scattering patterns.It is shown that multimode degenerate resonances at multiple frequency regimes appearing in a graphene composite structure due to the peculiar dispersion can be employed to resonantly overlap electric and magnetic multipoles of various orders,and,as a result,effective multifrequency superscattering with different engineered angular patterns can be obtained.Moreover,the phenomena of multifrequency superscattering have a high tolerance to material losses and some structural variations.Our work should anticipate extensive applications ranging from emission enhancing,energy harvesting,and antenna design with improved sensitivity and accuracy due to multifrequency operation.展开更多
Abstract A novel approach for the synthesis of shaped beam patterns in time-modulated antenna arrays(TMAAs)with static uniform amplitude and phase excitations is proposed in this paper.Based on the sideband radiation ...Abstract A novel approach for the synthesis of shaped beam patterns in time-modulated antenna arrays(TMAAs)with static uniform amplitude and phase excitations is proposed in this paper.Based on the sideband radiation in TMAAs,shaped beam patterns can be realized by only controlling the switch-on time sequences of the TMAAs.Differential evolution(DE)algorithm is adopted to optimize the time modulation parameters to obtain the desired flat-top and cosecant-squared beams and to suppress the sidelobe levels(SLLs).Simulation results of a time-modulated linear array(TMLA)and a timemodulated semicircular array(TMSA)demonstrate the effectiveness of the proposed approach for the synthesis of shaped beam patterns from TMAAs.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11504306 and 92050102)Fujian Provincial Natural Science Foundation(No.2017J05015)。
文摘Multifrequency superscattering is a phenomenon in which the scattering cross section from a subwavelength object simultaneously exceeds the single-channel limit at multiple frequency regimes.Here,we achieve simultaneously,within a graphene-coated subwavelength structure,multifrequency superscattering and superscattering shaping with different engineered scattering patterns.It is shown that multimode degenerate resonances at multiple frequency regimes appearing in a graphene composite structure due to the peculiar dispersion can be employed to resonantly overlap electric and magnetic multipoles of various orders,and,as a result,effective multifrequency superscattering with different engineered angular patterns can be obtained.Moreover,the phenomena of multifrequency superscattering have a high tolerance to material losses and some structural variations.Our work should anticipate extensive applications ranging from emission enhancing,energy harvesting,and antenna design with improved sensitivity and accuracy due to multifrequency operation.
基金This work was supported in part by the National Natural Science Foundation of China(Grant No.60971030)the Program for New Century Excellent Talent in University(No.NCET-06-0809)the 111 project of China(No.B07046).
文摘Abstract A novel approach for the synthesis of shaped beam patterns in time-modulated antenna arrays(TMAAs)with static uniform amplitude and phase excitations is proposed in this paper.Based on the sideband radiation in TMAAs,shaped beam patterns can be realized by only controlling the switch-on time sequences of the TMAAs.Differential evolution(DE)algorithm is adopted to optimize the time modulation parameters to obtain the desired flat-top and cosecant-squared beams and to suppress the sidelobe levels(SLLs).Simulation results of a time-modulated linear array(TMLA)and a timemodulated semicircular array(TMSA)demonstrate the effectiveness of the proposed approach for the synthesis of shaped beam patterns from TMAAs.
