本帖最后由 lijiqing 于 2010-11-19 16:25 编辑
前几天，zhshao521老弟的两个帖子，掀起了一个角反射器天线的热潮，引起坛友的极大兴趣。美中不足，原作是塞尔维亚文的，不少坛友嫌看着费力，只好望“角”兴叹。
Zhshao521老弟把火点起来了，希望它越烧越大。我也来加把柴！！
作者的另一个改进型的角反射器天线——《缩短型3D角反射器天线》，是在原天线基础上做了2项改进，原天线17.4dB，现17.9dB。这个是英文版。抽空把E文翻成了中文。
还是那句话，时间紧迫，水平有限，错误之处，敬请高手批评指正。
上图看看～～～～
原天线是这样：
改进后：
Shortened 3D Corner Reflector Antenna
Dragoslav Dobričić, YU1AW
缩短型3D角反射器天线
Abstract
概要
In this text two 3D corner reflector antenna modifications are described.
本文描述对3D角反射器天线的两处修改。
The first modification is regarding the input impedance decrease from about 72 ohms of the original antenna, to about 50 ohms, which made possible supplying with usual coaxial cables of 50 ohms impedance. This is achieved by adding a passive element to the existing active element. This decreased impedance while retaining antenna’s gain and its radiation diagram.
第一处修改是把原天线的输入阻抗从大约72欧姆降低到大约50欧姆，这样就能够和我们平常使用的50欧姆同轴电缆匹配了。这个修改是依靠在有源振子的基础上增加了一个无源振子实现的。
The second modification is regarding the alteration of the shape of the antenna by removing one piece of the bottom reflector surface. The result of this is smaller and more compact antenna with smaller resistance to the wind and accumulation of the snow, with very small change of radiation diagram and gain decrease of about 0.25 dB.
第二项修改是去掉天线底面反射体的一部分，其结果是天线更小更紧凑了，降低了风阻，减少了落雪的堆积。而方向图和增益只降低了很小的0.25dB。
The practical solution of the construction of Shortened 3D Corner Reflector Antenna for 2.4 GHz is given at the end of the text.
本文最后给出缩短型角反射器天线的实际结构。
Introduction
引言
The original design of 3D Corner Reflector Antenna was for the first time described in:
IEEE Transactions on Antennas and Propagation, July, 1974.
"Three-Dimensional Corner Reflector Array" by Naoki Inagaki (pp. 580-582).
3D角反射器天线最初发表在：电气和电子工程师协会会刊《天线和传播》，1974年7月号，Naoki Inagaki 先生的文章“三维角反射器阵列天线”第580-582页。
The precise and explicit results of computer analysis and simulation were reported in July 2003. by L.B. Cebik
W4RNL in the article: “The 3-D Corner Reflector” (www.cebik.com/vhf/3c.html).
精确的计算机模拟报告由L.B. Cebik
W4RNL先生发布在2003年7月的文章：“3D角形反射器” (www.cebik.com/vhf/3c.html)。
Fig. 1. Original 3D Corner Reflector Antenna.
图1：最初的3D角反射器天线
The antenna consists of three square reflector surfaces placed among each other perpendicularly to form half of the cube, and with the active element in the form of monopole at one of them, as shown in figure 1. This structure concentrates electromagnetic energy in relatively narrow beam, whose direction of maximum radiation is in the line with the large diagonal of the cube, which begins in the apex, i.e. under angle of 45 degrees between the beam and all three reflector surfaces.
天线由3个矩形平面反射器直立围成半个立方体，有源振子（单极天线）安装在其中一个反射器上，如图1所示。这种结构使电磁能量汇聚为狭窄的波束，最大辐射方向在从顶点开始的立方体最长的对角线上，也就是说，波束和3个反射面之间的夹角是45度。
The reflector surfaces’ dimensions are not critical. With the enlargement of the surfaces, antenna gain also increases, at first considerably and later on less and less.
反射面的尺寸不是最关键的。扩大反射面，天线的增益也会增加，开始时增加的较多，然后就越来越少了。
Our analyses revealed that the practical maximum of the gain is achieved before we expected so far.
我们的分析显示，实际上最大增益远远高于我们的预期。
The optimal dimension is about 2.8 wavelengths. Further dimension enlargement leads to more and more insignificant increase of the gain of the antenna, and for 3-3.5 wavelengths the practical gain maximum is achieved. Further enlargement of reflector surfaces has no meaning, because it does not lead to the gain increase, as shown in the figure 2.
最佳尺寸大约是2.8个波长，更大的尺寸对于增益来说就越来越没有价值了，到3-3.5个波长时，增益就达到极限了。反射板尺寸再大也没有意义了，不会带来增益的增长，见图2。
说我超过字数！！无法再贴了！！！
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