الفهرس | Only 14 pages are availabe for public view |
Abstract Polarization converters find wide applications in communications and radar. Conventional polarization converters suffer from heavy weight, complicated structure, losses, and / or narrow bandwidth. Polarization converters based upon electromagnetic band gap materials are low profile, light weight, efficient, and have large bandwidth. This thesis is concerned with millimeter wave polarization converters made of mushroom-like electromagnetic band gap materials. A simple procedure for the design of these converters is developed. One of the polarization converters designed transform linear polarization to another linear but the electric field is perpendicular to the incident field. Other polarization converters transform linear polarization to right-handed circular or left-handed circular. Different structures for polarization converters are designed. These structures are: (1) rectangular patch, (2) square patch with single slot, (3) square patch with two slots, (4) square patch with offset via, (5) uni-planar compact structure, and (6) slotted ring structure. Reconfigurable polarization converter with varactor diodes is designed to transform linear polarization to linear perpendicular or right-handed circular according to the values of the varactors. Reconfigurable polarization converter with square patch and three offset vias connected to switches is designed. The converter transforms linear polarization to linear perpendicular, left-handed circular, or right-handed circular according to thevia chosen. All simulations are carried out using the software packages HFSS and CST. |