Research And Design On Miniaturized Multi-octave Antenna

With the development of communication technology and integrated circuit,electronic equipment tends to be miniaturized,and it is required that the functional module units constituting such equipment have a smaller size and a more compact structure.As a key component of communication equipment,the performance of antenna has a direct impact on the quality of the entire communication equipment,so having research on the antenna adapting to miniaturized equipment is of great significance.In this paper,we focus on Vivaldi antenna and planar spiral antenna to study its miniaturization and broadband design technology.The specific content and work of this paper contains:1.A compact Vivaldi antenna is investigated and designed.Firstly,resistive loading and comb slot loading are carried out on the basis of conventional Vivaldi antenna,the operating frequency of the antenna is reduced,and the radiation pattern is improved.The dimension of the antenna is simulated in Ansoft HFSS.The overall size of the antenna is 139*140*1mm3,and the operating frequency is 0.42GHz~3GHz(S11<-10 d B)(a 150% relative bandwidth)and the gain ranges from-3.8 to 7.7d B,the radiation pattern is fine.Finally the compact Vivaldi antenna has been fabricated and tested,and the test results have been analyzed.2.A dual-polarized Vivaldi antenna is designed on the basis of the single-polarized Vivaldi antenna.The two single polarized antennas are placed orthogonally,to ensure the integrity of the antenna feed structure,the ports are not in the same plane.The ports operate in 0.47~3GHz(a 146% relative bandwidth)and 0.64~3GHz(a 130% relative bandwidth),the isolation between two ports is better than 20 d B,the gain of antenna is from-2.3d B to 7.7d B.The dual polarized Vivaldi antenna is fabricated and tested.The test results show the good performance of the antenna.3.A miniaturized planar spiral antenna working on 0.4~3GHz(a 153% relative bandwidth)is investigated and designed.Firstly,the traditional Archimedes spiral antenna is used as the radiating element,and it feeds through the Exponential microstrip balun.However,due to the large vertical dimension,the overall profile of the antenna is too large,so the straight balun is curved to reduce profile.And to get unidirectional radiation characteristic,a reflective back cavity is designed and loaded backside.Then because of the large size of the radiating unit,the traditional spiral line is loaded with sine wave to decrease the planar size.Finally the dimension of the antenna is 179.5*179.5*41.5mm3,compared with original design,the size of the novel spiral antenna reduced to 54.8%.The S11 parameter is less than-10 d B in the whole band,no beam splitting in radiation pattern,the gain is-5.5~4.5d B.The novel structure simulated and optimized in HFSS has been fabricated and tested.The test results are in good agreement with simulation results which indicates that miniaturization design is effective and feasible.