超材料在微波和光頻領(lǐng)域的理論和應(yīng)用研究.pdf

1、Ultra wide-band (UWB) filter is designed from defected ground structure of conducting plane or PEC (perfect electric conductor) with complimentary split ring resonator (DGS-CSRR).From Simulation results, the transmission

2、 bandwidth (BW) and fractional bandwidth (FBW) UWB at 10 dB below the transmission power are 2.48 GHz and 27.46％ respectively.These results have already been greater than the minimum requirement set by the Federal Commun

3、ications (FCC) of USA.The frequency dependent of DGS-CSRR of macroscopic properties permittivity(ε) and permeability (μ) of UWB resonator are are derived from the law of kinematic motions of free electrons of metals and

4、Maxwell's equations under the influence of extemal electromagnetic field forming Drude-Lorentz harmonic oscillator.Drude-Lorentz mode harmonic oscillator helps to track down the resonance frequency of UWB oscillator arou

5、nd which both ε and μ become simultaneously negative values.This scenario would bring unique properties of the materials, which do not exist naturally forming a special classification called metamaterial or double materi

6、al of negative refractive index (NIM) material.UWB made from such materials have attracted a great interest in both academic and industry in the past few years for applications in short range wireless mobile systems.This

7、 is due to the potential advantages of UWB transmission such as low power, high rate, immunity multi-path propagation and low interference.
　　On the other hand under optical frequency regime, the interaction of light

8、with free electrons in gold and silver nano-structore can give rise to collective excitations commonly known as surface plasrnons.Plasmons provide a powerful means of confining light between the metal and the dielectric

9、interfaces,which intern they can generate intense local electromagnetic fields and significantly amplify the signal derived from an analytical techniques from weak signals due to Raman scattering.With plasmon photonic si

10、gnals can be manipulated on the nano-scale, enabling integration with electronics.Furthermore the optica; responses of various geometrical gold or silver nano-shell with silica core are investigated by finite difference

11、time domain (FDTD) method.This method provides a convenient, symmetric, and general approach for calculating the optical responses of nono-struetural of arbitrary symmetry and geometry to an incident light wave.Propertie

12、s such as optical extinction cross-section (the sum of absorption and scattering cross-section), surface plasmon resonances (SPR) including longitudinal and surface plasmon resonances, enhancement of local electric field

13、 (ELEF) are extracted and dear with this method.The method is widely applied to uniform and non uniform gold and silver nano-shells with silica dielectric cores, aggregated or colloidal number of various shapes and size

14、of gold and silver nano-particles inside silica dielectric medium.It is also applied for optical characterization of naked and silica-coated gold and silver nano-particles inside a polymer.Eventually the results show tha

15、t defects and sharper edges of nano-particles of various forms and arrangements are significantly affecting the enhancement of the electric field for amplifying the weak signals called raman scattering.Latter on this ass

16、ists the development of surface-enhanced Raman scattering (SERS).SERS provides a sensitive meted for detecting trace levels of wide range of chemical and bioechmical compound absorbed on anno-structured plasmonic Au/Ag n