Performance Analysis Of Antennas Above Layered Media

Ground penetrating radar and ultra-wideband through-wall radar have been widely used in both military and civil area. The antenna is one of the key components of the radar and its performance directly affects the detection resolution of the system, positioning accuracy and ability of target recognition. In these systems, the performance of the antenna is partly decided by the structure of the antenna itself and also influenced by environments (ground, wall). The analysis shows that these antennas work above a number of stratified media (ground, wall). Therefore, the analysis of performance of the antenna above layered media is of great significance.In this dissertation, the research and analysis of the performance of the antenna above layered media are carried out. Three aspects, including the theory of layered media Green's function, the performance of narrow-band dipole antennas above the ground, and the performance analysis of broadband bow-tie antennas above the wall, are research focuses. The major contents are listed as follows:Firstly, layered media Green's functions are introduced. The derivation of the vector potential and scalar potential of spectral domain Green's function and transmission lines Green's functions are investigated. And a detailed analysis of the spectral domain Green's function transformed into the spatial Green's function is obtained.Secondly, the performance of a narrow-band dipole antenna above an infinite plane half-space is analyzed by the method of moments(MoM) based on mixed potential integral equations(MPIE), and the specific discussion of the influence of electrical parameters of the infinite ground on the antenna performance is obtained. The result proves the calculation correct.At last, the performance of broadband bow-tie antenna above a wall is analyzed by MoM based on MPIE, using RWG basis functions. According to the conclusions of the analysis, a novel bow-tie antenna with adjustable input impedance is proposed based on the traditional bow-tie antenna. The proposed antenna shows advantages of design simplicity and adjustment, which is capable of the requirement of radar system under complex and versatile environments.