共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
在解决射频识别(RFID)标签天线设计中阻抗计算速度慢的问题的过程中,针对其中较为复杂的阻抗耦合情况,该文提出一种基于多项式的弯折偶极子RFID标签天线阻抗预测方法。首先使用基于天线尺寸的阻抗变换与线性化假设建立模型假设;然后在具体的天线结构中收集数据并进行相关性分析与回归拟合验证假设正确性;最后实验验证使用该方法进行的阻抗预测相对于计算机仿真的准确性、高效性与普适性。试验结果表明,使用该方法替代计算机进行弯折偶极子RFID标签天线阻抗计算时,其预测阻抗相对于计算机仿真结果在保持较高预测准确率的同时极大地缩短了阻抗计算时间,同时该方法在中国应用频段上针对不同弯折次数的弯折偶极子RFID标签天线仍然适用。 相似文献
3.
4.
在解决射频识别(RFID)标签天线设计中阻抗计算速度慢的问题的过程中,针对其中较为复杂的阻抗耦合情况,该文提出一种基于多项式的弯折偶极子RFID标签天线阻抗预测方法.首先使用基于天线尺寸的阻抗变换与线性化假设建立模型假设;然后在具体的天线结构中收集数据并进行相关性分析与回归拟合验证假设正确性;最后实验验证使用该方法进行的阻抗预测相对于计算机仿真的准确性、高效性与普适性.试验结果表明,使用该方法替代计算机进行弯折偶极子RFID标签天线阻抗计算时,其预测阻抗相对于计算机仿真结果在保持较高预测准确率的同时极大地缩短了阻抗计算时间,同时该方法在中国应用频段上针对不同弯折次数的弯折偶极子RFID标签天线仍然适用. 相似文献
5.
6.
天线的输入阻抗是指天线输入端电压与电流的比值,它与天线类型、电尺寸大小、材料性质、馈电位置及周围环境均有关,文章介绍了几种天线阻抗的测量方法。 相似文献
7.
8.
设计有源天线的一种新方法 总被引:2,自引:0,他引:2
本文对用一种负阻抗变换电路同电小天线导线相结合构成的有源天线进行了理论分析.并给出了该有源天线稳定的工作条件.分析结果表明:用该方法设计的有源天线具有较高的灵敏度和较小的最佳天线尺寸.实验结果证实该方法有效. 相似文献
9.
前言因附雪(冰)和天线拉线更新工程等外部原因,会使中波发射机的天线阻抗大幅度变化。负载阻抗的变化,往往会引起发射机工作不稳定,甚至造成停播。特别对固体发射机来说,末级要专设防止损坏半导体管的 相似文献
10.
曹振平 《固体电子学研究与进展》2014,(4)
利用三维天线平板模型对托卡马克离子回旋共振加热天线阻抗进行模拟计算,并以托卡马克离子回旋共振加热简单环天线为例,计算得到不同条件下的天线阻抗。计算结果表明,天线结构尺寸、等离子体密度分布以及天线与等离子体间的距离参数对天线阻抗都有不同影响。结果有助于离子回旋共振加热天线的设计和阻抗匹配。 相似文献
11.
An efficient numerical approach to model antennas that include a microstrip element radiating in the presence of material layers is developed. The class of antennas considered is fed through the ground plane by a coaxial transmission line. The reaction integral equation is formulated by treating the coaxial aperture as part of the antenna. The substrate thickness can be arbitrary, making this numerical technique suitable for high-frequency applications. The effects of the substrate are also included in the analysis. Numerical results are obtained for the current distribution and input impedance. The algorithm is validated with experimental results 相似文献
12.
《Antennas and Propagation, IEEE Transactions on》2009,57(2):484-490
13.
Analysis of linear coaxial antennas 总被引:3,自引:0,他引:3
Jean-Fu Kiang 《Antennas and Propagation, IEEE Transactions on》1998,46(5):636-642
Two types of linear coaxial antennas, coaxial-colinear antennas, and slotted coaxial antennas are studied to check the possibility of using them as the base-station antenna in personal communication systems. The slot voltages and input impedance of linear coaxial antennas are obtained by using a transmission-line analysis where the radiation effect is accounted by a shunt and a serial admittance, respectively. The current distribution is obtained by solving an integral equation using the method of moments. The radiation pattern and directivity are then obtained from the current distribution and the reflection coefficient inside the coaxial cable. Factors analyzed include frequency, coaxial filling permittivity and segment number 相似文献
14.
Three kinds of mutual coupling between active printed antennas, due to respectively space waves, surface waves and feed line, are evaluated and expressed with analytical forms which are in good agreement with experiments. There are two problems associated when using thicker substrate to broaden the microstrip antenna bandwidth : increase in surface waves and coaxial line coupling effects, and deterioration of the radiation pattern. The solution to the problem is to make use of substrates with very low relative permittivity to put a Lecher-line instead of a coaxial line. The different couplings between all radiating elements have been taken into account to calculate the active impedance of the individual element and the perturbation of radiation characteristics for a scanned beam array at reception. 相似文献
15.
An impedance transforming balun feeder system has been devised for low-gain antennas such as quadrifilar helices and spirals, consisting of four coaxial cables and a microstrip circuit. The arrangement allows physically orthogonal `balanced pair' outputs with quadrature phasing, in space limited configurations 相似文献
16.
17.
18.
针对高功率天线的差分馈电和阻抗匹配问题,文中提出了一种基于同轴线结构加载铁氧体磁环的宽
带巴伦模型。双同轴线具有阻抗变换功能和较好的功率承载能力,铁氧体磁环改善了巴伦在低频时的输入匹配和
两个输出端口不平衡度。仿真和实测表明,此巴伦在0. 05~1. 24 GHz 内回波损耗低于-10 dB,去除3. 0 dB 系统插损
后单端插入损耗在1. 5 dB 以内,两端输出的相位不平衡度在5°以内,幅度不平衡度在2%以内。通过分析巴伦的电
磁热损耗场、温度场和应力形变场,验证了巴伦在高功率馈电下的工作性能,结果表明此巴伦在工作频带内能够承
受500 W 的功率。 相似文献
19.
The impedances of relatively long dipoles in an isotropic laboratory plasma have been measured at 9.2 GHz (X band). A helium plasma was generated by discharging a capacitor between electrodes in a cylindrical container ten free-space wavelengths in diameter. Impedance measurements were made in the decaying afterglow plasma at electron densities both above and below the critical electron density (10^{12} cm-3). The dipole antennas were fed from miniature solid-jacketed coaxial cables attached to a waveguide on which the voltage reflection coefficient was measured. The effect of plasma on the impedance of the dipole antenna was derived theoretically by treating the dipole as a dissipative transmission line. The theory described in a qualitative fashion the observed impedance variation with electron density for all the dipoles investigated. The measurements indicated certain antenna impedance properties, due to the plasma, which were not accounted for by the simple theory. 相似文献
20.
The use of the method of lines in the analysis of various circular antennas-circular patch antennas and various forms of monopoles is proposed and substantiated. The antennas considered are fed by coaxial lines. Impedance/admittance transfer procedures are developed, which allow to calculate the antenna input impedance by a successive transfer from the aperture through the different sections. The described relations are also useful for other applications 相似文献