Study of Ultra-Wideband Antennas with FVTD/DGTD Methods

Author: Diana Eremyan
Keywords: UWB antennas, FVTD DGTD methods, simulation
Annotation:

Nowadays the increasing number of required infotainment services (such as radio, TV, GPS, mobile communication, remote control, etc) forces the need for an increased number of antennas integrated into a modern vehicle. The integration of the high frequency services in present-day vehicles requires antennas, which often have to be placed very close to each other. This is the case with roof antennas that operate in different frequency ranges for Global System for Mobile communication (GSM), Universal Mobile Communication System (UMTS), Global Positioning System (GPS) and Satellite Digital Radio Service (SDARS) applications. Typical roof antenna systems contain ultra-wideband monopole antennas for mobile communication. UWB monopole antennas can be of various geometric shapes. In this diploma thesis planar UWB monopole antennas are investigated. At present there are a lot of numerical methods for simulations of antennas. Within this thesis, the FVTD – Finite Volume Time Domain and DGTD – Discontinuous Galerkin Time Domain simulation methods for analysis of high-frequency antenna systems are validated. These methods are tested and validated using measurements and other simulation approaches (MoM - Method of Moments, FEM – Finite Element Method, FDTD – Finite Difference Time Domain method). Application of FVTD and DGTD numerical methods for analysis of high-frequency antenna systems was chosen for several important reasons: • FVTD/DGTD methods allow describing complex antenna systems for high-frequencies range with several dielectric objects, while MoM is not very effective when arbitrary configurations with complex geometries or inhomogeneous dielectrics are considered. • FVTD/DGTD and FDTD are numerical methods for time domain calculations. But important difference between these methods is expressed in meshing of geometry. For FDTD method all geometry has to be represented with structured mesh (cuboids) and small details require a fine grid that extends over the entire computational domain. So FDTD has difficulties in modeling of non-rectangular objects, while in calculations with FVTD/DGTD methods unstructured meshes (tetrahedrons) permit accurate modeling of complex structures. • FEM is more suited for modeling of arbitrary surfaces and complex structures, however, it is frequency domain algorithm and coverage of wide-band frequency range needs number of several separated calculations. In case of FVTD/DGTD, using pulse excitation and Fourier transformation (FFT or DFT), frequency-domain characteristics can be retrieved over a large frequency band in a single computational run Objective of current diploma thesis is validation of FVTD and DGTD methods for modeling of high-frequency antennas. In the thesis are stated and solved the following tasks: • Preparation of the measurements samples and performing of the measurements for the UWB planar monopole antennas, GPS and SDARS patch antennas in EMCoS laboratory • Construction and simulation of antenna models using different software packages (EMCoS MTEC VLab, EMC Studio, ANSYS HFSS, CST Studio Suite) for validation of FVTD\ DGTD methods • Comparison of obtained simulation results with measurement data • Comparison of calculation times expended for simulations with different methods • Derivation of conclusions about FVTD/DGTD methods applicability in ultra-high frequencies range based on performed investigations

Lecture files:

Presentation: Study of Ultra-Wideband Antennas with FVTD/DGTD Methods [en]
Work: Study of Ultra-Wideband Antennas with FVTD/DGTD Methods [en]