Search for dissertations about: "explicit-implicit time-stepping"

Found 4 swedish dissertations containing the words explicit-implicit time-stepping.

2. 1. Shape and material optimization for antenna applications

   Author : Per Jacobsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; explicit-implicit time stepping; sensitivity analysis; Nitsche s method; total scattering cross section; shape and material optimization; array antennas; finite element method;

   Abstract : In this thesis, a gradient-based method for shape and material optimization fortwo antenna applications is presented: minimization of the active reflectioncoefficient for conformal array antennas; and minimization of the totalscattering cross section for cylindrical scatterers. The sensitivity of theobjective function with respect to changes of the shape and material of the geometry isexpressed in terms of the original field problem and an adjoint field problem. READ MORE

4. 2. A hybrid finite element method for electromagnetics with applications in time-domain

   Author : DAVID DEGERFELDT; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nitsche s method; antenna arrays; NASA almond; edge elements; scattering; explicit-implicit time-stepping; Maxwell s equations; Finite Element Method; mass lumping; stability analysis; Finite-Differences Time-Domain; periodic structures; shape and material optimization;

   Abstract : In this thesis, a new hybrid method that combines the Finite Element Method (FEM) with the Finite-Difference in Time-Domain (FDTD) method is presented. Tetrahedrons in the unstructured FEM region are connected directly to thehexahedrons in the structured FDTD region. READ MORE

5. 3. Optimization for scattering and radiation problems based on a stable FEM-FDTD hybrid method

   Author : Tomas Halleröd; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; finite-difference time-domain; finite element method; array antennas; electric and magnetic losses; pattern synthesis; shape and material optimization; explicit-implicit time-stepping; scattering;

   Abstract : In this thesis, a stable hybrid method combining the finite-elementmethod (FEM) and the finite-difference time-domain (FDTD) scheme forMaxwell's equations in two dimensions with both electric and magneticlosses is presented. It combines the flexibility of the FEM with theefficiency of the FDTD scheme. READ MORE

6. 4. Stable FEM-FDTD Hybrid Method for Maxwell's Equations

   Author : Thomas Rylander; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Finite Element Method; scattering; antennas; stability analysis; edge elements; Maxwell s equations; NASA almond; microwave circuits; mass lumping; proof of stability; explicit-implicit time-stepping; Finite-Differences Time-Domain;

   Abstract : In this thesis edge elements are applied to solve several problems in computational electromagnetics. In particular, a hybrid scheme joining the Finite Element Method (FEM) and the Finite-Difference Time-Domain (FDTD) algorithm is developed, tested and exploited. READ MORE