Research On UWB Pulse Antenna

In recent years,with the development of ultra-wide pulse technology and the improvement of their respective requirements in various engineering applications,the design indexes for ultra-wide pulse antennas are getting higher and higher.Therefore,the pulse radiation system is more important for ultra-wideband antennas in the time domain waveform fidelity and radiation beam width have made higher requirements.As an indispensable part of UWB technology,the performances of UWB antennas have a significant impact on the UWB system.Considering the necessity of antennas for ultrawideband systems,research on ultra-wideband pulse antenna technology is of great significance.This thesis combines the needs of underground target detection,takes the ultrawideband pulse antenna as the research object,and studies the technology of the antenna in the frequency domain and the time domain.Finally,this thesis designs two ultra-wideband pulse antennas: one is the dual-ridge waveguide TEM horn antenna,which loaded with a resistor and a semicircular structure,the other is a shielded Archimedes spiral antenna loaded with inductors and metal coils.1.Based on the radiation principle of the TEM horn antenna,a dual-ridge waveguide TEM horn antenna is designed,whose low limit frequency of 450 MHz.Since the ground exploration application requires the antenna frequency band to be extended to the low frequency as much as possible.it is proposed two dual-ridge waveguide TEM horn antennas with "resistances loaded" and "semi-circular structure combined with resistances loaded" after the simulation analysis.Through the final comparison,the "semi-circular structure and resistances" composite loaded method has better impedance matching at low frequency,making the antenna low limit frequency extending to 168 MHz,the return lossis greater than10 d B in the frequency band from 168 MHz to 1GHz,and the fidelity of the antenna in the time domain waveform is more perfect.The final optimized antenna is processed and tested,and the test results verify the antenna's performances in the frequency domain and time domain.In addition,two underground target detection experiments are designed to confirm the practicability of the antenna in engineering applications.2.Aiming at the coupling characteristics between the transmitting and receiving antennas of the ground penetrating radar system,a shielded Archimedes spiral antenna loaded with inductances and metal coil is designed.The loading of the cylindrical shielded cavity greatly improves the antenna gain and reduces the backlobe,which has unidirectional radiation characteristics.After the shielded cavity is loaded,the reflection coefficient of antenna is increased.The loading of inductances and metal coil solves this problem.Finally achieved good impedance matching of the antenna in the 310MHz-2GHz frequency band,and the Axial Ratio Value of the antenna is relatively low,with good circular polarization performance.The final optimized antenna is processed and tested,and the test results verify the impedance bandwidth,pattern and circular polarization of the antenna in the frequency domain.In addition,the designed antenna is used as a transceiver antenna to analyze its mutual coupling characteristics,and the results show that the mutual coupling of the circularly polarized transceiver antenna with the opposite rotation is smaller than that of the linearly polarized transceiver antenna.