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螺旋天线的快速分析及宽带化设计 总被引:3,自引:3,他引:0
研究了一种快速计算螺旋天线电特性的新方法,并结合遗传算法对天线进行了宽带、小型化设计。采用直线段对法向模螺旋天线进行划分,应用合成基函数及合成检验函数的矩量法对阻抗矩阵进行了降阶处理,节省了求解矩阵方程所需的时间和存储量。结合遗传算法对加载法向模螺旋天线上的加载集总元件的值、加载位置以及匹配网络参数进行一体化优化设计,并采用Sherman-Morrison-Woodbury公式快速求解加载后的矩阵方程,提高了优化设计的效率。最后,成功设计了一副工作在100~1000MHz的宽带小型化螺旋天线。 相似文献
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文中基于单极粗振子展宽带宽理论,采用一种新型加粗套筒单极子辐射体的实用模型来展宽套筒单极子天线的阻抗带宽,并利用有限元法(FEM)对其驻波和辐射特性以及天线各参数进行了分析。在此基础上,设计了一副工作在108MHz~420MHz频段、电压驻波比小于3.0的实用套筒单极子天线,计算结果与实测结果吻合良好。 相似文献
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针对星载无缆化通信的需求,研究了展宽印制天线工作带宽的方法。设计了星载小型化宽带全向印制天线,通过三维全波电磁仿真软件(CST)进行了仿真分析与优化设计。在此基础上加工了天线实物样件,并对其电性能进行了测试。仿真结果表明该天线具有小型化、宽带、全向等特点。 相似文献
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套筒天线的发现一定程度上拓展了线天线的带宽,但是传统的套筒天线在VSWR<8的条件下带宽只有4:1。文献[1]提出了一种新型的宽带套筒天线,在VSWR<1.5的情况下可以达到1.81:1的阻抗带宽。本文对这种新型宽带套筒天线中特殊的结构进行讨论,主要讨论端部加载对该新型天线S11的影响,经研究发现端部加载可以很大程度上拓展天线带宽,在同样尺寸的情况下将传统套筒天线的阻抗带宽(VSWR<1.5)由1.03:1拓展到1.81:1,即带宽拓展了75.7%。在S11<-10d B的条件下由1.09:1拓展到2.05:1,即带宽拓宽了88.1%,在天线没有小型化处理时可以拓展到3.81:1。因此这为天线阻抗的良好匹配提供一种新的方法,同时也很好的弥补了传统套筒天线结构上不连续的不足。 相似文献
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超短波天线在舰船飞机上应用很广,天线的小型化有利于提升其隐蔽性、稳固性,因此对天线的小型化设计显得异常重要。采用加载集总元件和宽带匹配网络的方式,设计了一款新型超短波天线。将宽带匹配网络做成一个微带电路结构与天线辐射单元直接相连的一体化设计,进一步减小了天线的长度;采用 Matlab 和 HFSS 软件联合仿真,并运用遗传算法优化计算全部集总元件的具体数值。天线在100 MHz~400 MHz频段范围内的驻波系数 VSWR(电压驻波比)小于3,水平方向全向辐射。天线和匹配网络总的物理长度仅为255 mm,实现了小型化的要求。制作了天线实物并测量,实测天线参数与仿真参数吻合较好,达到了设计目标。 相似文献
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研究学习了加载技术及其与其他小型化、宽带化技术的组合应用,并介绍了加载的优化设计,通过最优化分析寻求加载的最优位置、加载形式、元件值,从而设计满足指标要求的宽带小型化天线。由于天线的方向系数、效率、带宽和体积尺寸等构成矛盾的关系,如何协调和折衷上述关系获得最佳天线结构,成为宽带小型化天线设计的核心问题。研究表明,将加载和其他技术的整合应用是未来天线设计的发展趋势。 相似文献
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本文介绍了一种VHF机载全向发射天线的设计方法。文中首先介绍了采用加载技术实现VHF天线的小型化,并分析了加载对增益的影响,然后采用遗传算法得出了一种宽带匹配网络,实现了宽带匹配,最后给出了实际天线的实测结果。 相似文献
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Sleeve antenna with ground wires 总被引:1,自引:0,他引:1
Pocklington's integral equation for a sleeve antenna with ground wires is formulated. By applying the Galerkin method to this equation, a sleeve antenna, a monopole antenna with ground wires, and a sleeve antenna with ground wires are analyzed, and numerical results for these antennas are compared with measured data. The sleeve antenna features the leakage current on the surface of the coaxial feeder, suppressed by a sperrtopf, but it is mismatched with the 50-Ω feeder. The monopole antenna with inclined ground wires may be adjusted to match the 50-Ω feeder, but the leakage current induced on the feeder cannot be neglected. It is found that the sleeve antenna with ground wires has the advantages of both antennas 相似文献
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《Vehicular Technology, IEEE Transactions on》1978,27(4):174-181
The measured values of energy deposited in simulated human tissue exposed for one minute in the immediate vicinity of 800 MHz portable radio transmitters are presented. The deposited RF energy was evaluated by temperature measurements. The portable radio used in the tests had a 6-W experimental transmitter operating at 840 MHz. Two different antennas were tested for energy deposition: a sleeve dipole and a resonant whip. The two antennas have given substantially different results indicating different field structures near the two radiators. The experiments with flat slabs have shown that the sleeve dipole deposits higher levels of power density than the resonant whip in the near field although the length of the latter radiator is about half the size of the former. The temperature profiles generated by both antennas inside the head of the simulated operator indicate the presence of a "hot spot" about 1 in below the surface of the temporal bone. This phenomenon was not detected previously at lower frequencies. The short antenna exposes the eye of the operator to more intense power deposition than the sleeve dipole. The temperature increases measured during the investigation are so small that no thermal damage to tissue should be caused by normal use of the portable radio. 相似文献
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复合材料垂尾隐蔽式短波天线研究 总被引:1,自引:0,他引:1
为研究复合材料垂尾对机载短波天线输入阻抗和辐射特性的影响,分析了不同机载隐蔽式短波天线的结构和性能,提出了一种基于复合材料垂尾的新型回线天线结构,并利用基于时域有限差分法的仿真软件XFDTD对这种位于机垂尾前缘的隐蔽式回线天线和传统的机载套筒天线分别进行了建模和仿真。根据仿真结果分析并总结出了复合材料垂尾对这两种机载短波天线输入阻抗和辐射特性的影响情况。通过与传统回线天线的比较,验证了新型回线天线的可行性和优势。仿真结果对实际机载短波天线的研究和设计有一定的参考价值。 相似文献
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ZHANG Ze-wei ZHANG Ming-fang 《通信对抗》2008,(3)
介绍了一种加粗的套筒单极天线,并作为测向单元使用。运用HFSS电磁仿真软件进行参数优化,在单元驻波与水平面增益满足工程情况下有效降低了天线高度。将这种套筒单极天线组成圆阵,在得出阵列电磁特性的基础上再运用最小二乘法分析了圆阵测向性能。结果表明,该测向天线阵在灵敏度、测向精度及阵列高度上都有一定的优势,特别适合于一些运动平台安装使用。 相似文献
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Yang D Bertram JM Converse MC O'Rourke AP Webster JG Hagness SC Will JA Mahvi DM 《IEEE transactions on bio-medical engineering》2006,53(3):533-537
We report a novel coaxial antenna for hepatic microwave ablation. This device uses a floating sleeve, that is, a metal conductor electrically isolated from the outer connector of the antenna coaxial body, to achieve a highly localized specific absorption rate pattern that is independent of insertion depth. This floating sleeve coaxial dipole antenna has low power reflection in the 2.4-GHz IMS band. Ex vivo experiments confirm our numerical simulation results. Index Terms-Ablation, coaxial aperture antennas, finite element methods, floating sleeve, microwave heating. 相似文献
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Experimental studies are reported of several coaxial structures useful us embedded antennas and transmission lines. These include the insulated coaxial line with extended inner conductor, the insulated dipole with choke section, and the insulated sleeve dipole. The purpose of the experiments is to confirm theoretical calculations that involve numerous approximations. 相似文献