Research And Design On New Types Of Dipole Antenna

With the rapid development of wireless communication systems,the number of customers for wireless communication is increasing day by day which result in higher requirements on the speed of communication.Antennas,as the most critical device in wireless communication,play an important role in the quality of communication.Antennas,with more excellent electrical performance parameters,can meet the increasing demands of wireless communication systems.This article focuses on two new types of dipole antennas,namely the low-profile dipole antenna with low profile applied to the base station and the wide beam circularly polarized cross dipole antenna used in the Beidou navigation system.The main content is divided into the following sections:1.This paper has designed a low profile magneto-electric dipole antenna.By designing the new folding ring structure as a magnetic dipole antenna,the multi-fold technique is adopted to reduce the antenna cross-section and reduce the height from 0.25? to 0.087? while maintaining excellent electrical performance parameters.The antenna is dc grounded by using coaxial feed which satisfies the requirement of many outdoor antennas.Simulation results show that the frequency range of 2.36GHz-3.3GHz,in the frequency range of 2.55 GHz to 3.2GHz,the gain stabilized at 9.5 ± 0.5dBi,the ratio of front to back of greater than 18 dB,the cross level of E-plan and H-plan of less than-45 dB and-20 dB respectively.The measured results show that the operating frequency range of 2.4GHz to 3.0GHz,the gain stable at 8 ± 0.5dBi,the ratio of front to back greater than 18 dB,which meet the design requirements.2.This paper has designed a printed cross-dipole dipole antenna with a new feed method.Equivalent square coaxial cable,and the slotted technology which applied in the outer surface which achieve a new type of unbalanced printed circuit board-balanced feed mode,thereby broadening the impedance bandwidth.The simulation and measured results show that in meeting the requirements of S11?-10 dB,the frequency range is 1.8GHz-3.2GHz.Furthermore,the quadrifilar half-length folding technique is adopted to broaden the axial ratio beamwidth of the cross-dipole dipole antenna.The simulated and measured 3dB axial beamwidths are 148° and 122°,which is 48° higher than the original non-folded dipole antenna.The technique of loading the metal round table as the reflecting surface improves the gain beamwidth and the low elevation gain.The simulation results show that the 3dB gain beam width broadens from 90° to 125°,elevation gain of 10° and 30°increased by 1.8dBi and 1dBi respectively.The height of cross-dipole dipole antenna has reduced from 45 mm to 30 mm with printed PCB technology and three-dimensional all-metal structure.3.This paper has designed a cross-dipole dipole antenna used in high-precision navigation and positioning system.Using double-length anti-clockwise folding technology,the 3dB AR beamwidth broadens by 16° compared with the original non-folded dipole antenna.The Balun-fed,stepped impedance conversion and the loading round table are used as the reflecting surface to broaden the beamwidths of cross dipole antenna.In the S-band,the measured and simulated 3dB gain beamwidths are 130° and 123° respectively.The measured and simulated 3dB AR beamwidth is about 106°.