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介绍了一种特殊形状的飞行器通信天线——腰形天线。用曲线坐标系时域有限差分法(NFDTD)对该天线进行了分析,并给出了一种新诠释,所计算出的辐射特性与实测结果吻合较好。结果表明:该天线能保证飞行器在复杂机动飞行条件下通信联络的畅通,且较好地解决了喷口火焰对天线辐射特性影响的难题。 相似文献
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针对客户终端设备(Customer Premise Equipment, CPE)的应用需求,设计了一种低剖面双频圆极化天线。在2.45 GHz,采用了4个偶极子单元阵列产生水平极化全向辐射,并采用内部接地圆环贴片结构产生垂直极化全向辐射。将两部分结构通过耦合器有效连接起来,从而产生了全向圆极化辐射特性。在5.8 GHz,采用了贴片结构产生了定向圆极化辐射特性。通过双工器将2个频段的结构合并起来,实现了低剖面双频圆极化天线。实测结果表明,天线在2个频段均有较好的圆极化辐射性能,验证了该天线设计的有效性。 相似文献
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人体对移动通信手机天线辐射特性的影响 总被引:3,自引:0,他引:3
本文用时域有限差分法成功地模拟了移动通信中常用的单极天线手机的辐射特性,并考虑了实际使用条件下天线与人体的作用,计算得到了受人体影响时的天线辐射方向图的辐射效率。 相似文献
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当对称锯齿形天线带有小接地板时,呈现一种背向辐射的特性。文中给出了实测的背向辐射方向图。这种天线可能发展成为一种新的反射面天线的线极化馈源。 相似文献
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任意极化波的功率传输效率计算及其对天线测量精度的影响 总被引:1,自引:0,他引:1
在测量圆极化天线辐射特性时,无论采用何种极化的测试信标天线,都会存在极化损失,即功率传输效率小于1,由此引入的测量误差是信标天线及待测天线极化特性的函数,因此需要对测量数据进行误差分析以及适当的修正。本文导出了任意两个椭圆极化波在一般情况下功率失配因子随轴比γ和轴倾角τ变化的计算公式,对工程中常见的几种情况进行了定量分析计算,讨论了功率失配校正因子的取值范围,以及对天线辐射特性测量精度的影响。 相似文献
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《Microwave Theory and Techniques》1981,29(3):266-270
A coaxial waveguide amplitude commutation feed system has been developed for application to the scanning circular array antenna problem. A dominant TEM mode and a pair of orthogonal TE/sub 11/ modes suitably excited at the input of a coaxial waveguide feed are employed to generate a simply commutatable low-sidelobe discrete amplitude distribution at the peripheral output ports of the coaxial circular array feed. The major advantages of the coaxial commutator feed compared to other circular array feed types are the broad bandwidth and small insertion loss simultaneously achieved with a simple feed geometry. The design and measured performance capability of a 30-percent RF bandwidth low-sidelobe coaxial commutator feed are described in detail. 相似文献
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The mutual coupling effects between a finite phased array of dipoles and its feed network are analyzed. The feed network is typically a corporate feed consisting of split-tee power dividers cascading to form a certain power distribution over the aperture. A simple iterative approach is used to solve the interaction between elements and feed. The radiation of a finite dipole array are first found for a given voltage excitation. These radiation impedances are then used as loads for the feed network, and the n +1 port network problem is analyzed. Due to the interaction between the feed network and dipoles, the antenna parameters such as mismatch, antenna pattern, and gain are all affected. These effects can be determined from the analysis of the network representation. Numerical results for a typical phased array with a corporate feed show that the resultant VSWR of the feed pattern degradation is due to the mutual coupling effects 相似文献
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A method is presented for accurately modeling a monopole or dipole antenna fed by a coaxial line. The base of the monopole is attached to a conducting plane through which the coaxial feed line extends to the feed. The feed structures considered are easily adaptable to physically rugged forms and are simple to construct. Equivalent models for the three regions of the structure are devised and coupled integral equations for aperture fields and surface currents are formulated to enforce the boundary conditions. Three variations of the feed configuration are discussed and the reflection coefficient of the antenna feed is determined from the data obtained from the solutions of the coupled integral equations. Computed reflection coefficient values are shown to agree well with values measured on laboratory models. 相似文献
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针对卡塞格伦天线系统对馈源的要求,设计了一种Ka频段双口双模馈源,可与X频段馈源组合成体积较小的双频段馈源。采用圆环状的和差比较器结构,降低了双频段馈源的体积,通过添加过渡阶梯、圆柱销钉与金属调配板等设计,改善了双频段馈源的性能。测试结果表明,在绝对带宽2 GHz范围内,S和口、E差口与H差口驻波比均小于2,3个端口间的隔离度均大于25 dB。测试频率的和方向图在±60°时的归一化增益均在-14~-20 dB范围内,初级归一化和方向图的对称性较理想,差方向图的零值深度均小于-25 dB,满足卡塞格伦天线对馈源设计的指标要求。 相似文献
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Dual-polarized dielectric resonator antennas 总被引:1,自引:0,他引:1
Yong-Xin Guo Kwai-Man Luk 《Antennas and Propagation, IEEE Transactions on》2003,51(5):1120-1124
Two high input-isolation dual-polarized dielectric resonator (DR) antennas are presented in this communication. First, a slot-coupled feed technique with two narrow slots forming a "T" configuration is employed to design a dual-polarized DR antenna. Input isolation exceeding 35 dB has been obtained in the band for this design. Secondly, a hybrid feed mechanism with a coplanar waveguide (CPW) feed and a slot feed is used to achieve a dual-polarized DR antenna. A vertical strip is added at the center strip of the CPW feed to improve the coupling to the DR antenna. Also, input isolation exceeding 35 dB has been obtained in the band. Good cross-polarization levels less than -20 dB in the broadside direction are attained. The measured far-field radiation patterns are stable in the passband and the measured gains are around 5.5 dBi for the two feed ports of both cases. 相似文献
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用FDTD和物理光学混合法分析毫米波抛物面天线 总被引:6,自引:0,他引:6
抛物面天线通常的分析方法是几何光学法和物理光学法,对于电大尺寸的抛物面天线这两种方法都可以得到较好的结果,对于电小尺寸馈源的抛物面天线,馈源方向图不仅取决于辐射器本身的辐射特性,其馈电结构对馈源方向图也有较大的影响,在此情况下,用上述方法得到的结果与实验结果之间有较大的误差.利用FDTD可以把整个馈电结构纳入计算域中,得到辐射器完整的近区场,由等效原理可求出抛物面上电流分布,从而用物理光学方法计算抛物面天线远区场.本文用这种混合方法分析计算了毫米波波导裂缝作为辐射器的抛物面天线,计算结果和测试结果相当吻合,证明了方法的有效性. 相似文献
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反射面天线设计的关键就是通过选择合适的喇叭馈源边缘照射电平以追求天线的高性能(增益,旁瓣电平,
效率等)。本文主要利用实例验证了标准反射面天线馈源喇叭的优选边缘照射电平,分析了赋形反射天线馈源喇叭的优选
边缘照射电平,给出了标准反射面和赋形反射面在设计中各自馈源喇叭的优选边缘照射电平。从而可以在设计工作中对
于不同形式的反射面天线有针对性的设计馈源喇叭的边缘照射电平。 相似文献
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The experimental development of a 1:6.535 scale model line feed for the Arecibo spherical reflector is described. The 14.7-ft long model at 2810 MHz simulates a 96.6-ft feed at 430 MHz capable of illuminating the full 1000-ft aperture of the reflector. The feed design requirements are discussed and an experimental program is outlined in which the necessary line source parameters were established using a number of leaky cylindrical test sections. Experimental measurements of both the near and far fields of the model feed are described and typical results are quoted and discussed. Finally, some results obtained after installation of a full size feed in the reflector are given and compared with predictions based on the model data. 相似文献