Miniaturization Research And Engineering Application Of Ultra-wideband Antennas

As the volume of wireless communication devices continues to decrease and the operating frequency band continues to develop into a wide frequency band,various techniques for broadening the bandwidth of the antenna and reducing the size of the antenna have been widely studied and intensively studied.This paper first introduces the miniaturization method of antenna design,and on this basis,it has been miniaturized for different types of ultra-wideband antennas.The main research contents of the thesis are as follows:1.Miniaturization design of ultra-wideband Vivaldi antenna: Firstly,based on the meandering technology and close-range loading technology,an ultra-wideband Vivaldi antenna with a small size is designed.By combining slotting and close-loading the low-end cutoff frequency is clearly reduced over the measured bandwidth ranging from 2.2GHz to 20 GHz.Then a miniaturized Vivaldi antenna based on terminal resistance loading is designed under the same size conditions.The final antenna has a working frequency range of 1.04 GHz to 8.5 GHz,and the antenna size has been greatly reduced.2.Helical antenna design: The axial mode helical antenna has a relatively stable radiation pattern in the whole working frequency band,but its circular polarization performance will decrease with the decrease of the number of spiral turns.Short distance loading is employed to improve the impedance matching performance and circularly polarized radiation characteristics.By this means,the number of solenoids can be cut down to reduce the height of the helical antenna.3.Miniaturized conformal array design: A hyper-wideband microstrip antenna cone conformal array is designed.Based on low-profile butterfly-slot microstrip antenna the conformal array is designed.In view of the shortcomings of the measured results,the miniaturization of the antenna element is improved.The miniaturization improvement uses the "wall" floor structure to improve the impedance matching of the antenna,and reduces the low frequency cutoff frequency of the antenna,and the miniaturized unit has also achieved good application in the array.