共查询到20条相似文献,搜索用时 109 毫秒
1.
针对频率较低时对数周期天线(LPDA)具有较大纵向尺寸,给出以曲线单元作为LPDA 的振子,以实现小型化的方法。采用曲线单元加长了LPDA 振子的电流路径,实现了天线的小型化;通过采用三角、正弦、矩形三种线型单元作为LPDA 的振子,研究了不同线型的小型化效率。对设计的三种线型LPDA 进行了仿真研究,结果表明:用曲线振子作为
LPDA 的振子是LPDA 小型化的有效措施,其中矩形线型振子LPDA 相比传统LPDA,尺寸缩小了19%;曲线振子LPDA的小型化效率主要受曲线长度的影响,与振子的形状和宽度也有关系。 相似文献
2.
3.
闪电电磁脉冲卫星接收天线设计初步探索 总被引:1,自引:1,他引:0
针对卫星轨道闪电电磁脉冲(LEMP)的信号特征以及接收环境的限制,提出了卫星轨道接收LEMP的天线设计参数,并据此设计了对称振子天线和对数周期振子阵天线。计算出了两种天线的辐射阻抗,输入阻抗,增益曲线,驻波比等参数,还给出了对数周期振子阵天线的各参数曲线。最后对两种天线进行了比较。对称振子的特点结构简单适合于当前应用。对数周期天线的接收性能优于对称振子天线,更适合于专门的电磁脉冲探测试验卫星。 相似文献
4.
5.
平面双频单极天线研究 总被引:2,自引:1,他引:1
研究了一种小型化的平面双频天线,利用一个斜F加倒L图形结构并通过在天线结构中的电感平衡加载来设计一种平面单极双频天线.它具有接地板小且天线低端谐振点频带宽的特点,为平面双频单极天线的小型化设计提供了一种新的方案. 相似文献
6.
王颍辉 《中国电子科学研究院学报》2013,8(1):96-99
采用感应电动势法分析了对数周期振子天线,对对数周期振子天线的终端传输线影响进行了认真的研究,最后在保证电气指标最优的情况下,设计出结构尺寸最小化、强度最大化的终端短路对数周期振子天线. 相似文献
7.
8.
9.
本文首先分析了高斯曲线对称振子的辐射特性。然后介绍了高斯曲线振子对数周期天线(LPDA)的设计方法。在此基础上设计了一种增益大于10dBi的高斯曲线振子LPDA,并给出了HFSS8.0软件的仿真结果。以及实际制造的模型的实测结果。 相似文献
10.
设计了一种最大辐射方向仰角可调的缩比变形对数周期天线。对对数周期天线变形,改变天线主体和振子的旋转角,使得该对数周期天线的最大辐射方向在一定范围内连续可调。增加X型反射器,有效改善了前后比,增加了天线增益。这种可调振子旋转角的对数周期天线能够在1~2 GHz实现电压驻波比(VSWR)小于2,俯仰角从25°至90°连续可调。相比传统对数周期天线,该天线除了具备宽带特性外还具备低仰角、俯仰可调等性能。 相似文献
11.
Wakabayashi R. Shimada K. Kawakami H. Sato G. 《Electromagnetic Compatibility, IEEE Transactions on》1999,41(2):93-99
Two types of broad-band antennas are widely used for electromagnetic interference (EMI) measurements in the frequency range from 30 to 1000 MHz. Log-periodic dipole antennas (LPDA) are mainly used for the range above 300 MHz and biconical antennas for the range less than 300 MHz. These two antennas have linear polarization. However, EMI measurements can sometimes be more conveniently made with an antenna having circular polarization and so we propose an improved LPDA, which has circular polarization. This LPDA has a second array of dipoles so arranged that each dipole of the second array has a quarter-wavelength phase difference from that of the corresponding dipole of the standard LBDA array for the given radiation field. For this reason, we named it a cross-element LPDA. The cross-element LPDA does not need a broadband 90° hybrid junction to produce circular polarization. We calculated the height pattern and the frequency characteristics of the classical site attenuation (CSA) for the cross-element LPDA when used for both transmitting and receiving, as well as the antenna factor. Moreover, we calculated the normalized site attenuation (NSA) when the cross-element LPDA is used for receiving or for both transmitting and receiving 相似文献
12.
13.
In this paper, new methods for further reducing the size and/or increasing the bandwidth (BW) of a class of miniaturized slot antennas are presented. This paper examines techniques such as parasitic coupling and inductive loading to achieve higher BW and further size reduction for this class of miniaturized slot antennas. The overall BW of a proposed double resonant antenna is shown to be increased by more than 94% compared with a single resonant antenna occupying the same area. The behavior of miniaturized slot antennas, loaded with series inductive elements along the radiating section is also examined. The inductive loads are constructed by two balanced short circuited slot lines placed on opposite sides of the radiating slot. These inductive loads can considerably reduce the antenna size at its resonance. Prototypes of a double resonant antenna at 850 MHz and inductively loaded miniaturized antennas at around 1 GHz are designed and tested. Finally the application of both methods in a dual band miniaturized antenna is presented. In all cases measured and simulated results show excellent agreement. 相似文献
14.
15.
Considerations for millimeter wave printed antennas 总被引:3,自引:0,他引:3
Calculated data are presented on the performance of printed antenna elements on substrates which may be electrically thick, as would be the case for printed antennas at millimeter wave frequencies. Printed dipoles and microstrip patch antennas on polytetrafluoroethylene (PTFE), quartz, and gallium arsenide substrates are considered. Data are given for resonant length, resonant resistance, bandwidth, loss due to surface waves, loss due to dielectric heating, and mutual coupling. Also presented is an optimization procedure for maximizing or minimizing power launched into surface waves from a multielement printed antenna array. The data are calculated by a moment method solution. 相似文献
16.
17.
Phasing stubs are employed to achieve a cophase current distribution in microstrip rectangular patch arrays. This technique, originally proposed for resonant long wire antennas by Franklin, avoids spurious radiation from half-wavelength connecting transmission lines as used in conventional patch antenna arrays. A slot-radiator model is derived to describe the basic radiation mechanism of the resultant new type of antenna and experimental results for the slot radiation resistance are given. The design of a 13-element resonant array for 12 GHz is presented together with measured radiation patterns. 相似文献
18.
19.