| With the rapid development of modern communication technology, the sizes ofcommunication electronic equipments are increasingly miniaturized, and their abilityto process information is also increasingly intelligent and broadband. So, the designof an antenna with compact size and high performance is the active demand of theantenna technology development. In recent thirty years, the printed antenna hasbecome one of the fastest growing branches of miniaturized antenna field due to thecontinuous improvement of the microelectronics technology and circuit boardprinting process. In order to adapt to a variety of wireless communicationequipments, there is no doubt the multiband, broadband and broadband circularlypolarized technique for printed antennas must be developed. In this paper, combinedwith the requirements of all kinds of wireless communication system, printedmultiband antenna, printed ultra-wideband antenna, printed circularly polarizedantenna and array antenna have been studied intensively. The author’s majorcontributions are follows:1. Printed multiband antennas are studied. According to the requirements ofreceiving multiple frequency signals by wireless communication device, three kindsof printed multiband antennas are designed.(1) A trident-shaped dual-band printedmonopole antenna with improved branch and top loading structure is designed,which can cover PCS and WLAN bands;(2) A tri-band printed monopole antennawith branches structure and improved ground plane is investigated, which can coverWLAN and WiMAX bands and have good omni-directional radiation patterns;(3)Also, it is given a compact triple-band printed monopole antenna with parasitic patch,bending branch and improved ground plane.2. Printed ultra-wideband (UWB) antennas and method of achievingband-notched characteristics are investigated.(1) Aiming at requirement of UWBcommunication systems, a printed UWB antenna with fan-shaped structure is designed.(2) In order to restrain the potential interference on UWB system from the others, Basedon the fan-shaped printed UWB antenna, two printed UWB antenna respectively withsingle and dual band-notched characteristics are proposed。(3) Meanwhile, Based on therectangular printed UWB antenna, a dual band-notched printed UWB antenna withC-shaped and U-shaped slots is given; After that, it is presented that a tripleband-notched printed UWB antenna with I-shaped slots defected ground structure,which can restrain the potential interference on UWB wireless communication systems from WLAN, WiMAX and C-band satellite communication systems.3. Printed quadrifilar helical antennas and feed networks are presented andstudied. In view of conventional resonant quadrifilar helical antennas with narrowerbandwidth and ordinary feed networks with big size can not meet the need of themodern circularly polarized wireless communication systems, a broadband printedquadrifilar helical antenna with tapered spiral metal arms and short circuit parasiticmetal arms is investigated; Moreover, a miniaturization feed network based onout-of-phase power divider with double-sided parallel striplines structure andWilkinson power divider is presented. The printed quadrifilar helical antenna and thefeed network expand the working frequency bands and reduce the occupied space.4. Printed planar circularly polarized antennas are proposed.(1) Inconsideration of higher requirements of modern wireless communication device onthe impedance bandwidth and the axial ratio bandwidth of circularly polarizedantennas, a kind of printed planar circularly polarized antenna with tapered curvedradiation stripes based on Archimedes spiral is designed.(2) After that, the taperedcurved structure based on Archimedes spiral is applied to the printed planar slotantenna. Thus, a printed circularly polarized tapered curved slot antenna is presented.The measured results show that these circularly polarized antennas have very wideimpedance and axial ratio bandwidth.5. Printed circularly polarized array antennas applied to satellite communicationsystems are studied. It is given a printed Archimedian spiral antenna working at UHFband. Based on these, a kind of rectangular circularly polarized phased array antennawith27antenna elements is investigated. The discussions are focused on how toimprove the polarization purity and restrain cross-polarization. Finally, it is presented atype of arrangement way which can effectively reduce the cross-polarization level ofthis phased array antenna. Then the scanned radiation out-of-roundness and the gain ofthe phased array antenna are given. |
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