Design Of Nanofilters Based On The Lumped Parameter

In the domains of microelectronics, radio frequency and microwave, the theory ofcircuit based on the lumped parameter (e.g., capacitor, inductor, resistor, etc.) is apowerful tool in theory-analyzing and designing, and the lumped parameter is aneffective simplified mode in modeling and analyzing the function in the systematiccircuit unit. By applying this mature theory, transplanting the circuit net constructed bythe lumped components in the classical circuit into infrared or optical frequency meansa new circuit-designing method could be found in this frequency. The direct assumptionwas to realize it by simply scaling the dimensions, but a mere scaling of the circuitcomponents used at radio and lower frequencies to the infrared and optical domainsmay not work, because metals change their conducting properties in the optical domain.To circumvent these problems, a new nanocircuit constructed thought based on thelumped parameter----metamaterial based nanocircuit was adopted.In this paper the equivalent relationship between the derivations of thenanoparticles and the lumped components, and the lumped parameter net constructedwith the nanoparticles were discussed. They were demonstrated in the following fourparts:In the first part, the background, definition, property and research&developmentsituation of the metamaterial based nanocircuit was briefly introduced, then thesignificance of the research and the prospect in applying as well as the main contents ofthe research were demonstrated.In the second part, by applying the analogy theory from optical circuits andclassical magnetic systems, the equivalent of the nanoinductors, nanocapacitors, andnanoresistors in the optical circuit was discussed. The validity of this theory was provedby some numerical simulations performed using the commercially available finiteelement method (FEM) software COMSOL Multiphysics. In the process of analogizingthe optical nanocircuit in the concentric circles, the leakage flux and geometricalresonances was existed between the components and components, the components andfree spaces. These leakage flux and geometrical resonances could couple with free spacearound the components, and lead some negative influence to the function of equivalentnanocircuits.In the third part, in order to avoid the unexpected effect aroused in the leakage fluxand geometrical resonances mentioned in the second part, the concepts of opticalnanoinsulators and nanoconnectors were proposed in accordance with the analogy of theclassical circuit. After confirming the material property of the nanoinsolators andnanoconnectors, the function of these nanocomponents in the optical circuit was verified; then in the three-dimensional ranked, the numerical simulation proved that thesenanoinsulators and nanoconnectors were effectively restricted the flux leakages andsurface plasmon polaritons among the components.In the fourth part, with the equivalent theory and methods of lumped nanocircuitcomponents concluded in the above paper, a functional optical filter was designed. Thecomparison between the simulated results and the circuit response was fairly goodqualitatively. This showed that the lumped circuit theory was successfully applied in theinfrared and optical frequency.