| Pulse antenna and ultra-wideband antenna have been widely used in ultra-wideband radar, ground penetrating radar, and wireless communication. The performance of antenna has important influences on the performance of system. Combined with the contents of the National Natural Science Fund of China, the Program for New Century Excellent Talents in University of MOE, and the Research Fund for Doctoral Program of Higher Education of China, the characteristics and the methods of analysis and design of pulse antenna and ultra-wideband antenna with properties of miniaturization and integration are studied in theory and practice in this dissertation, and several kinds of low-profile pulse antennas and ultra-wideband antennas are proposed. The influences of antenna on the design of ultra-wideband pulse waveform are also studied. The influence of human body on the characteristics of Ultra Wideband antenna is also studied.The main work and innovation points in this dissertation include:1. The relationship between the transient current, peak value of radiation pulse, late-time ringing, distortion of the square loop antenna and the parameters of antenna structure has been studied in time domain. The results demonstrate that the correlation between the radiation signal and the exciting signal of loop antenna loaded properly can be rather high, which is suitable for coherent receiving.2. Based on the study of time-domain characteristics of antenna, suggestion of modifying the oscillating coefficient remarking characteristics of radiation pulse is proposed.3. By the methods of modifying the feeding structure, the size of disc, and the flare angle of cone, variations of input and radiation characteristics of discone antenna with antenna structure have been analyzed, and a low profile pulse antenna with main radiation direction in horizon plane has been designed.4. The method of improving the low frequency performance of antenna by adding arm at one side of the cone top is proposed. By extending the length of the current path on the antenna, this method can effectively lengthen the electrical length of antenna while the physical height of antenna maintains invariable. By this approach, low-frequency performance of the discone antenna can be improved, the profile can be reduced, and the properties of low profile and minimization can be obtained.5. Radiation characteristics of wire dipole antenna and physical mechanisms of reflection and radiation generated at the end of antenna have been studied, and the method of improving amplitude-frequency characteristics of dipole antenna is given. Leaf-like ultra-wideband antenna and leaf-like directional pulse antenna loaded by dielectric block on one side beside the feeding point are proposed, which give the sort of dipole antenna good property of ultra-wideband. A kind of low-profile directional pulse antenna with small radiation late-time ringing is also obtained.6. Taking example for the third-order differential Rayleigh pulse radiated by the dipole antenna which is resistance loaded, the influences of antenna on the design of pulse waveform in ultra-wideband system are analyzed. The studies have found that the radiation pulse will be broadened after passing through the antenna, and the spectrum will shift entirely to the lower frequency band. Therefore, the third-order differential Rayleigh pulse with narrower pulse-width or high-order differential Rayleigh pulse is required to be the excitation signal, in order to ensure that the spectrum of radiation pulse after passing through the antenna will meet the requirement of FCC.7. The influence of human body on the characteristics of Ultra Wideband antenna is studied.
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