| The stealth and anti-stealth techniques of antenna has become an important subject. The conventional investigations on this subject are mainly based on continuous wave. Due to the property of ultra-wide-band, time-domain impulse is considered as an efficient way of anti-stealth. Currently, impulse sources with duration of nanosecond and peak power of several GW can be manufactured, which make it possible to utilize impulse detection devices for practical applications. Therefore, it is emergent and important to study the scattering characteristics of antenna illuminated by strong impulse and to find the relationship between these characteristics and antenna structure. These kinds of information are of great importance on the study of stealth and anti-stealth. With the subject of time-domain scattering of antenna array, this dissertation is aimed to study the time-domain scattering mechanism of antenna scattering and find the relationship between scattering characteristics and antenna structure, and look for ways to reduce the time-domain scattering.The main work and innovation points in this dissertation include:1. By studying the available definitions of radiating and scattering parameters of antennas in time-domain, several parameters are proposed which can be used to describe the time-domain scattering characteristics of antenna.2. Parallel computer cluster has been constructed, and the FDTD code was also modified into parallel format. In addition, the efficiency of parallel calculation has been studied. The results indicate that parallel FDTD code based on MP1 can calculate the time-domain scattering of large antenna array efficiently.3. Time-domain scattering characteristics of log-periodic antenna (PLA), plane dipole antenna array with and without reflectors are studied systematically for the first time. Variations of scattering impulse peak value, energy distribution and frequency spectrum with different feeding modes, impulse width, incident directions and polarizations are analyzed.4. Time-domain scattering mechanism of dipole antenna array has been studied. The interrelationship between the scattering impulse waveform, spectrum and array structure is analyzed. The range of impulse incident angle, within which the size of the array can be identified according to the backscattered field, is studied. The relationship between the angle range and the impulse width was also studied. Based on the time-frequency technique, the time-frequency characteristics of backscattered field with different incident impulse width are analyzed.5. Three methods were proposed to reduce the peak value of time domain scattering field of dipole antenna array with reflector, which are, the taper loading in reflector edges, toothed edges and wedged edges of the reflector. The results demonstrate that the effect on suppressing the peak value of scattering field is dramatic by employing the methods of taper loading edges and toothed edges.6. Time-domain scattering characteristics of microstrip antenna array with probe feeding and microstrip line feeding have been studied. Contributions of microstrip patches and ground plane to the scattering field are analyzed individually by using the method of scattering field separation. The results show that little difference on the time-domain scattering characteristics can be found between the microstrip antenna array with narrowband feeding network and the array without feeding network but open-circuit each element. It is also found that the scattering outside resonant frequency is mainly contributed by the ground plane.
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