| The greatest triumph in mobile communication service boosts the development of thefourth-generation (4G), and it creates high demand for unidirectional antennas to accommodatewireless communication system with excellent electrical characteristics such as wide impedancebandwidth, low cross-polarization, and stable gain over the operating band.However, most popular wideband unidirection antennas do not have a very stable radiationpattern over the operating bandwidth. Their radiation patterns can change substantially dependingon frequency. This thesis presents proposals for the design of a new wideband magneto-electric dipoleantenna for wireless communication on the basis of analyzing the characteristics of the radiationpatterns of electric dipole and magnetic dipole, and the antenna has stable gain as well as radiationpattern over the operating band. Base on the theory of composite right/left-Handed transmissionline(CRLH-TL), the magnetic dipole part of the antenna is realized by loading periodical capacitiveon a loop antenna, therefore, the current flowing along of the loop is kept in phase. And thecoplanar bowtie-dipole works as electric dipole part of the design, and it provides wide bandwidth forthe entire antenna. Furthermore, this antenna is fed by double-sided parallel-strip line(DSPSL), whichcan also work as an impedance transformer and improve the impedance bandwidth.After simulating and analyzing, the antenna is fabricated and measured, it shows that theantenna bandwidth is38%(VSWR1.5)from1.9GHz to2.75GHz, which conclude2110MHz~2200MHz,2300MHz~2400MHz and2500MHz~2690MHz LTE band with stableradiation pattern.And its max gain can reach8.4dBi with variation of1dB.And thecross-polarization levels over the operating band are below-20dB, which is suitable for engineeringapplications. |
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