Exciting the Low Permittivity Dielectric Resonator Antenna Using Tall Microstrip Line Feeding Structure and Applications

Abstract

The development of wireless communications increases the challenges on antenna performance to improve the capability of the whole system. New fabrication technologies are emerging that not only can improve the performance of components but also provide more options for materials and geometries. One of the advanced technologies, referred to as deep X-ray lithography (XRL), can improve the performance of RF components while providing interesting opportunities for fabrication. Since this fabrication technology enables the objects of high aspect ratio (tall) structure with high accuracy, it offers RF/microwave components some unique advantages, such as higher coupling energy and compacted size. The research presented in that thesis investigates the properties of deep XRL fabricated tall microstrip transmission line and describes some important features such as characteristic impedance, attenuation, and electromagnetic field distribution. Furthermore, since most of traditional feeding structure cannot supply enough coupling energy to excite the low permittivity DRA element (εr≤10), three novel feeding schemes composed by tall microstrip line on exciting dielectric resonator antennas (DRA) with low permittivity are proposed and analyzed in this research. Both simulation and experimental measured results exhibit excellent performance. Additionally, a new simulation approach to realize Dolph-Chebyshev linear series-fed DRA arrays by using the advantages of tall microstrip line feeding structure is proposed. By using a novel T shape feeding scheme, the array exhibits wide band operation due to the low permittivity (εr=5) DRA elements and good radiation pattern due to the novel feeding structure. The tall metal transmission line feed structure and the polymer-based DRA elements could be fabricated in a common process by the deep XRL technology. This thesis firstly illustrates properties and knowledge for both DRA element and the tall transmission line. Then the three novel feeding schemes by using the tall transmission line on exciting the low permittivity DRA are proposed and one of the feeding structures, side coupling feeding, is analyzed through the simulation and experiments. Finally, the T shape feeding structure is applied into low permittivity linear DRA array design work. A novel method on designing the Dolph-Chebyshev array is proposed making the design work more efficient.