共查询到20条相似文献,搜索用时 15 毫秒
1.
The log-periodic V-dipole antenna (LPVA) operating in the3lambda/2 mode is analyzed numerically using the projective technique. The antenna is treated as a parallel connection of an array of V-dipoles and a feeder transmission line. This decoupling of the circuits enables one to obtain the dipole currents simply by considering the array of V-dipoles as a boundary value problem and solving the necessary integral equations. The currents can then be used to give the various properties of the antenna. Effects on the antenna behavior obtained by changing its parameters are illustrated, and general characteristic curves presented. 相似文献
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Varying the spacing between the transposed transmission line feeder and the radiating elements of the loop-coupled antenna is investigated experimentally using far-field swept-frequency techniques. An optimum spacing is found in the sense that anomalous frequency performance is minimized. A theory using dispersion relationships is developed and used to explain some of the experimental phenomena observed. 相似文献
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V. V. Pavlovskii I. I. Gundareva O. Yu. Volkov Yu. Ya. Divin V. N. Gubankov 《Journal of Communications Technology and Electronics》2013,58(9):951-955
The results of the spectral analysis of a high-temperature superconducting (HTSC) log-periodic antenna integrated with a HTSC Josephson junction (JJ) and operating, in this case, as a test resonant system are presented. Current-voltage characteristics of the JJ and dependences of its differential resistance on the voltage across the JJ are measured at a temperature of 5 K by varying the JJ critical current by an external magnetic field in order to extend the operating frequency range of the spectral analysis. The low-frequency boundary of the spectral analysis, which is determined by temperature fluctuations, is lowered to 64 GHz. The equivalent circuit of an integrated device consisting of the JJ and the log-periodic antenna is analyzed. The real part of the antenna admittance is reconstructed from experimental data in the frequency range 65–1200 GHz. Experimental results are compared with the results of numerical calculation. 相似文献
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宽频带小型对数周期天线的设计 总被引:1,自引:0,他引:1
对数周期天线是结构简单,性能优良的超宽频带天线。利用一副对数周期天线可以覆盖整个短波波段,广泛应用于短波通信中。在超短波和微波波段,在解决好其纵向长度后,对数周期天线实际应用也很广泛。通过分析对数周期天线的基本原理,利用矩量法(伽略金)对其分析计算,结合工程实际要求,设计出一副在超短波到微波波段符合一定技术指标的小型化对数周期天线。测试结果表明,该天线在设计频带内、增益高、尺寸小、结构简单、符合工程设计要求。 相似文献
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Design of a stripline log-periodic dipole antenna 总被引:1,自引:0,他引:1
Campbell C. Traboulay I. Suthers M. Kneve H. 《Antennas and Propagation, IEEE Transactions on》1977,25(5):718-721
A procedure is given for designing a two-layer stripline log-periodic dipole (LPD) antenna array. Measured input impedance and far-field characteristics are demonstrated for a 12-element array for 1-2 GHz operation that are in good agreement with design specifications. 相似文献
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F. F. Dubrovka N. N. Litvin S. Ye. Martynyuk M. N. Bilanovskii G. A. Yena 《Radioelectronics and Communications Systems》2007,50(4):194-196
The paper is devoted to investigation of ultra-wideband logarithmically periodic vibrators of mirror antennas. The vibrators
have the form of cophasal antenna arrays consisting of two log-periodic dipole radiators, comprising a pyramid arranged in
the H-plane. The asymmetric and symmetric types of excitation of these dipoles are considered, with their calculated and measured
characteristics included.
Original Russian Text ? F. F. Dubrovka, N. N. Litvin, S. Ye. Martynyuk, M. N. Bilanovskii, G. A. Yena, 2007, published in
Izvestiya VUZ. Radioelektronika, 2007, Vol. 50, No. 4, pp. 26–30. 相似文献
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Matrix methods for analysis of dipole antenna arrays have been applied to general computer programs but often require large amounts of computation time for multiple-frequency analysis of electrically long arrays, since most of the computations must be repeated for each frequency. It is shown how the special geometry of a leg-periodic dipole antenna may be exploited within the general framework of matrix methods to permit multiple-frequency analysis without the need to repeat all computations for each frequency. The computation of antenna currents at one frequency is made use of in solving for currents at a different frequency; the time consuming matrix inversion step is required only once. 相似文献
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Kosta S. Singh M. Agarwal N. Singh A. 《Antennas and Propagation, IEEE Transactions on》1970,18(5):701-701
Attempts are made to verify Kosta's [1] theory of log-periodic dipole (LPD) antenna, for LPD structures with separation angle (psi ) between two halves not equal to zero (psi neq 0deg ), using Monser's [2] experimental results. It is shown that this theory is quite capable of explaining the electrical properties of the LPD withpsi neq 0deg . 相似文献
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Results are presented for the frequency dependence of the propagation constant of uniform microstrip patch arrays that allow the bandwidth limitations of log-periodic patch arrays to be deduced. It is found that direct coupling of the patch to the feed line limits the log-periodic bandwidth to about a 2:1 frequency range. However, the introduction of series reactance into the equivalent circuit such as by the use of overlaid patches indicate that log-periodic action over a very wide bandwidth is possible which will then be limited by the uniform substrate and production tolerances. 相似文献
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The feasibility of operating a compact antenna test range at 35 GHz has been demonstrated. A compact range of simple construction has been shown to have a performance only slightly inferior to the performance at X-band. Diffracted rays from the edges of the source reflector can degrate the purity of the electric field. This has been investigated and sucessfully controlled by serrating the rim of the reflector. 相似文献
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对用于导引头的平面印刷对数周期天线进行FDTD分析,采用曲折振子来减小天线尺寸,以满足实际应用需求。制作出实验天线,测试分析表明该天线用于导引头是可行的。 相似文献
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提出了通过优化馈管间距、馈电点位置和馈管长度三个特征参数,实现对数周期天线驻波比最佳化的方法,并对四个不同频段的天线进行了理论仿真分析和实测验证.实验结果表明:当馈管间距为馈管边长的1.45倍,馈电点位置为最短振子长度与天线间隔常数乘积的2倍,馈管端部到最短振子的长度为馈电点到最短振子长度的1.15倍时,天线的驻波比达到最优状态.这些理论分析与实验结果为对数周期天线的工程应用提供了重要依据,也为最优化设计提供了一种更有效的方法. 相似文献
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The input admittance of the rectangular cavity-backed slot antenna is investigated. The slot is assumed narrow so that the voltage distribution in its aperture is sinusoidal. Equations which represent the input admittance of this slot, backed by a rectangular cavity in which a single propagating wave is assumed to exist, are given. Calculations based on these representations are compared to available measured data. As the depth of the cavity increased the resonant frequency decreased and the bandwidth became narrower. Input admittance curves as a function of electrical slot length are also presented for several size cavities. 相似文献
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对数周期偶极子天线全空间可变相位中心 总被引:2,自引:0,他引:2
导出了直线阵列在全空间中存在可变相位中心的条件,得出了由非相似单元组成的直线阵列(如对数周期偶极子天线)不存在全空间可变相位中心,但在E面和H面独立存在各自的可变相位中心的结论.证明了对数周期偶极子天线(LPDA)在E面和H面有不同的可变相位中心.采用矩量法(MoM)分析了LPDA的E面和H面可变相位中心,计算结果表明:虽然在LPDA的主波束范围内其相位中心变化很小,可以作为"视在相位中心",但是这种"视在相位中心"仍然在E面和H面是不重合的.此外,"视在相位中心"随着频率沿着集合线移动. 相似文献
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An efficient numerical technique based on the modal-expansion method in conjunction with a recursive algorithm is developed for a multilayer insulated monopole antenna fed by a coaxial transmission line. The modal-expansion analysis is facilitated by introducing a perfectly matched boundary (PMB) at a variable height over the ground plane of the monopole. The current distribution and input admittance are computed by finding the expansion coefficients of the electromagnetic field expressions. Numerical results for the input admittance of a dielectric-coated monopole antenna and an air-insulated monopole are compared with experimental ones available in the literature. Good agreement is achieved. Calculated results for the effects of various parameters on the input admittance of an air-insulated monopole antenna are presented and discussed 相似文献