Sharif Digital Repository

The existing transmission line models of plasmonic nanostructures are modified in this thesis to study the electromagnetic characteristics of nano-plasmonic structures in a more efficeint yet accurate enough fashion. First, rectangular plasmonic cavities made by carving dielectric rectangles within a metallic region are modeled by trasnmission lines of finite length being appropriately terminated at their both ends. The resonance conditon in the proposed model yeilds the resonance frequencies, quality factors, and mode profiles of its correspondig plasmonic resonator. The accuracy of the proposed model is assessed by using the fully numerical finite-difference time-domain method (FDTD)... 

Nowadays, every society tries to adjust its development’s orientation towards sustainable development. Construction projects have a significant share of every country’s economy. Construction waste management is one of the most important issues affecting sustainability. Construction waste management and waste minimization programs in construction projects not only can save resources and help the economy, but also can enhance a country’s development toward sustainable development. Designing process can be an effective phase in waste management among different stages of a project life cycle. Considering the significant number of concrete building constructions in Iran, the aim of this research... 

In this study, we simulated and analyzed a plasmonic waveguide modulator based on single layer graphene. It includes a graphene sheet, which sandwiches between two layers of silicon dioxide. Then, some gates are arranged on either side of the waveguide on a periodic structure. When an electric field is applied perpendicular to the waveguide plate, the Fermi level of graphene under the gates, changes. Detailed analysis is performed by the method of lines based on Maxwell's equations along the propagation direction of the waveguide. Computation of the multi-gate device starts by examining the effect of Fermi level. Transmission coefficient of the magnetic-field norms of the modulator is... 

Nowadays dielectric substrates are widely used in Microwave Integrated Circuits. These substrates are made layer by layer in order to have favorable mechanical and thermal properties. The materials of the layers are usually different from each other and often each layer is a combination of different materials. This difference in material type and manufacturing method causes the substrate to have a different permitivity coefficient in two major directions, namely parallel and perpendicular direction. In fact, the electric field observes a different permitivity coefficient in each direction. This causes a problem in circuits that have both perpendicular and parallel electric field...