德拉甘菱形扇面天线的设计思路和制作实例

Quados Sector Antenna for 2.4 GHz WiFi

Dragoslav Dobri i , YU1AW

WIFI频段 2.4GHz 德拉甘菱形扇面天线

Introduction

导论

After successful construction of the Amos [1] and Inverted Amos [2] sector antennas, which are vertically polarized when they are used as sector antennas with wide

horizontal and narrow vertical diagrams, I decided to try to construct an antenna with similar performance, but with horizontal polarization. The bi-quad antenna was very interesting as a starting point design and I tried to add more quad elements to get higher gain and narrower vertical diagrams. After some time of computer

optimization I found that bi-quad antennas with two more quads added gave a very small increase in gain compared to the original bi-quad antenna, and the expected 3 dB difference is impossible to achieve. Another two quads were added and after optimization, the results showed an even smaller increase in antenna gain than expected. I was convinced that some problem existed and that simply adding quads does not give the expected increase in gain of roughly 3dB with every doubling of element numbers. I expected that the increase in gain will not follow 3dB for system doubling due to lower currents in far quad elements but overall gain was even lower then that expectation.

在成功地制成阿摩司和反转阿摩司扇形天线之后（作为宽水平方向图和窄垂直方向图的扇形天线，它们是垂直极化的），我决定制作一个类似的天线，但是要水平极化的。菱形天线是符合这些要求的，我决定试着增加菱形振子的数目，来获得更高的增益和更狭窄的垂直方向图。经过若干次计算机仿真优化，我发现增加两个菱形只能增加很小的增益，而期待的3dB差别不可能达到。新加的两个菱形经过优化，结果显示增加的增益比预想的小得多。我相信一定存在什么问题，简单地增加菱形不能取得预期的每两个菱形增加大约3dB增益的效果。我猜想，增益不会随着菱形的成倍增加而增加预期的3dB，是因为远处的菱形振子电流减小，使总增益低于预期。