Design And Development Of High Radiation Efficiency Antenna

High radiation-efficiency antennas have attracted increasing interest due to their wide application in commercial and military fields.However,due to the low working frequency band,the current antenna with high radiation efficiency has many problems,such as large size,high cost and difficult design.As the antenna with high radiative efficiency plays an important role in anti-terrorist activities and fire rescue,it is extremely important to design an antenna with the advantages of miniaturization,broadband and high radiative efficiency.In this thesis,a compact electromagnetic dipole antenna with high radiation efficiency is designed by using the complementary principle of electric dipole and magnetic dipole.The main content of the thesis is as follows.Firstly,the research background and application significance of high radiation-efficiency antennas are briefly analyzed,and the research status of high radiation-efficiency antennas at home and abroad are summarized and analyzed.After comparing and analyzing the antenna models such as butterfly antenna,electromagnetic dipole antenna,mixed water dielectric resonator antenna and Vivaldi antenna,the electromagnetic dipole antenna was finally selected as the basic antenna model for the design of high radiation efficiency antenna.Secondly,the basic principles of electric dipole and magnetic dipole are analyzed,and the theoretical formulas of impedance matching and Wilkinson power divider are derived,which lay a solid foundation for the following antenna design.After that,the complementary mode of electromagnetic dipole antenna was further studied,and finally a compact electromagnetic dipole element antenna with high radiation efficiency was designed based on Shark antenna.Later,cut off the double-cone antenna as the electric dipole and insert the magnetic dipole behind it to realize the direction pattern complementarity.Meanwhile,to improve impedance matching,a transition structure from coaxial to parallel plate is designed.The working frequency band of the electromagnetic dipole element antenna is 0.75 GHz ~ 2.31 GHz,its relative bandwidth reaches 100.96%,the size is 200mm×200mm×160mm,and the maximum gain can reach 8.5dB.In the whole frequency band,the radiation efficiency of the unit antenna reaches more than 94%,realizing high radiation efficiency.Then,a wideband one in three Wilkinson power divider is designed to match theelectromagnetic dipole element antenna.The linear array of 1×3 electromagnetic dipole antenna is realized by combining the power divider and the element antenna,and the optimal array is obtained by optimizing the spacing between the element antennas.The working frequency band of the electromagnetic dipole antenna array is 0.75 GHz ~2.17 GHz,its relative bandwidth reaches 97.26%,the maximum gain reaches 11.5dB,and the radiation efficiency of the whole frequency band exceeds 84%.Finally,the advantages and disadvantages of the designed electromagnetic dipole element antenna and its array are analyzed and summarized.The prospect of high radiative efficiency antenna is prospected.