Research And Design Of Wideband Antenna Used In Ground Penetrating Radar

Since the complexity of region and particularity of manner on exploration, Ground Penetrating Radar has a higher requirement than ha normal radar system. According to a GPR project requirement, Archimedean spiral antenna for vehicular GPR and H-shaped slot antenna for airborne GPR are analyzed and designed using FDTD method in this thesis.In the first part of this thesis, the FDTD method is briefly introduced, and the antenna computing model are built using it. Near-Field computing model and Near-Field to Far-Field Transform are presented. Result parameters of the FDTD program are introduced, and the program is checked.In the second part of this thesis, the affect of parameters of Archimedean spiral antenna to the input impedance is analyzed by FDTD method, appropriate parameters of the antenna for the project is selected. Microstrip balun is designed for this antenna based on the input impedance. Then the antenna is actually produced and measured. The effect on VSWR for antenna by changing absorbing structures placed in reflecting cavity is analyzed. According to the analytical result, a new absorbing structure is designed and actual measurement is carried out. The application of the antenna in vehicular GPR is introduced.In the third part of this thesis, radialization principle of the H-shaped slot antenna is firstly introduced, and the H-shaped slot antenna is modeled using FDTD method, the affect of parameters of H-shaped slot antenna to the input impedance is analyzed. Appropriate parameters of the antenna for the project is selected. The antenna and its microstrip balun is actually produced and measured. The result shows that the measured data is approaching to the simulated data, and it meets the requirement of the airborne GPR project.