Online

Ahmed, Amr

Electrical Engineering

2014

MS

This thesis presents a novel antenna structure that satisfies the challenging requirements of an air coupled high speed ground penetrating radar (GPR). The desired GPR system is to achieve high spatial resolution and accurate inspection results while scanning at relatively high speed for highway pavement and bridge deck inspection. This work utilizes the Ultra Wide Band (UWB) antenna design to achieve both physical and electrical requirements imposed. The design procedure starts with a short survey to discuss typical UWB antennas used for GPR applications, and various tradeoffs of each type specifically when used for Air Coupled GPR applications. Our structure anatomy is presented, followed by a theory introduction that mainly focuses on achieving good impedance matching throughout the proposed antenna structure. A proof-of-concept MATLAB model is created to evaluate the preliminary physical dimensions that can achieve minimum reflections at antenna's feed point. These dimensions are then used in SolidWorks to create a 3D model that is imported later in HFSS to obtain accurate electromagnetic characteristics. Furthermore, fine tunings are performed to the antenna structure to optimize both gain and impedance matching. The SolidWorks 3-D structural model is finally used for antenna fabrication. The measurements recorded from the field experiments using the prototypes manufactured are compared to the simulation results confirming our initial findings. Both measurements and simulation results demonstrated very small reflection loss across the 700 MHz ~ 6 GHz frequency band with a very high directed gain and radiation efficiency.