Hi, I'm Mr. T, the product guy at RF elements.

大家好，我是射頻元件公司的產品經理 T 先生。

If you find our videos useful, consider subscribing to our channel, like or leave a comment.

如果您覺得我們的視頻有用，請考慮訂閱我們的頻道，點贊或留言。

In our previous video, we've explained what an antenna radiation diagram is and how to read it.

在上一段視頻中，我們解釋了什麼是天線輻射圖以及如何讀取天線輻射圖。

Most frequently, the datasheets of antennas show the gain of an antenna in the form of a 2D polar plot.

天線數據表通常以二維極座標圖的形式顯示天線的增益。

We believe that having a 3D radiation diagram is more useful than the 2D version.

我們相信，三維輻射圖比二維輻射圖更有用。

And in this video, we will explain why.

在本視頻中，我們將解釋其中的原因。

So what is the 3D radiation diagram anyway?

那麼，三維輻射圖到底是什麼呢？

Generally, the gain radiation pattern says what is the radiation intensity of the electromagnetic fields an antenna radiates in any direction.

一般來說，增益輻射模式表示天線向任何方向輻射的電磁場的輻射強度。

A 2D pattern gives this information in a selected two-dimensional cut, most commonly in two planes perpendicular to each other.

二維圖案在選定的二維切面上提供這些資訊，最常見的是在兩個相互垂直的平面上。

You can already guess that the two cuts probably give a limited information compared to the full 3D radiation pattern showing the gain in all three dimensions.

您已經可以猜到，與顯示所有三個維度增益的完整 3D 輻射圖相比，這兩個切面提供的資訊可能很有限。

Imagine the simplest example of an isotropic antenna.

想象一下最簡單的各向同性天線的例子。

It is a theoretical antenna that radiates with the same intensity in every direction.

這是一種理論上的天線，向各個方向輻射的強度相同。

Let's place it at the origin of the XYZ coordinate system.

讓我們把它放在 XYZ 座標系的原點。

Drawing radiation intensity in a given direction as vectors and connecting their tips, we get a surface which is the 3D radiation diagram.

將給定方向上的輻射強度繪製成矢量，並將它們的頂端連接起來，我們就得到了一個表面，這就是三維輻射圖。

Since an isotropic antenna radiates with the same strength in all directions, the radiation pattern has the shape of a sphere.

由於各向同性天線在各個方向上的輻射強度相同，是以其輻射模式呈球形。

It's that simple.

就是這麼簡單。

The same can be done for any antenna out there.

任何天線都可以這樣做。

Consider it's placed at the origin of the Cartesian coordinate system.

考慮將其置於直角座標系的原點。

The direction and strength of its radiation at any point in space can be expressed by a vector with direction and amplitude.

它在空間任意一點的輻射方向和強度可以用一個具有方向和振幅的矢量來表示。

Connecting the tips of all the vectors forms a spatial image we call 3D radiation diagram.

將所有矢量的頂端連接起來，就形成了一幅空間影像，我們稱之為三維輻射圖。

Since no real antenna is isotropic, let's have a look at a real-life example, a parabolic dish antenna.

由於沒有一個真正的天線是各向同性的，所以讓我們來看一個現實生活中的例子--拋物面碟形天線。

It focuses the energy of the electromagnetic wave in the direction of its main axis where it's the strongest.

它將電磁波的能量集中在電磁波最強的主軸方向。

Besides that, it also has side lobes that are weaker than the main lobe and are mostly unwanted especially in the unlicensed frequency bands where the interference is the biggest problem.

除此以外，它還有比主頻帶弱的邊葉，這些邊葉大多是不需要的，尤其是在干擾問題最大的非授權頻段。

Same thing here as with the isotropic antenna.

這裡的情況與各向同性天線相同。

We can plot the vectors from the origin of the whole spherical surface, but now, because the parabolic dish does not radiate equally everywhere, the vectors will have varying lengths depending on the direction.

我們可以繪製出從整個球面的原點出發的矢量圖，但現在，由於拋物面碟形面並不是在所有地方都同樣輻射，所以矢量的長度會因方向不同而不同。

Connecting the tips of the vectors, we get the 3D radiation pattern of this antenna.

將矢量的頂端連接起來，我們就得到了該天線的三維輻射模式。

The 3D radiation diagram provides a complete information about the gain of an antenna since it shows the gain in every possible direction in 3D space.

三維輻射圖提供了天線增益的完整資訊，因為它顯示了三維空間中每個可能方向的增益。

You cannot do better than that.

沒有比這更好的了。

This is why it is generally more useful than the 2D plot which is obtained from the 3D plot anyway.

這就是為什麼它通常比二維圖形更有用的原因，因為二維圖形是從三維圖形中獲得的。

In some fields, the 2D diagram can be enough, but when examining the side lobes of an antenna is vital to the particular application, for example, in the wireless internet service provider industry where many operators leverage unlicensed frequency bands, the noise propagated through the side lobes does a lot of harm.

在某些領域，二維圖就足夠了，但當檢查天線側葉對特定應用至關重要時，例如，在無線互聯網服務提供商行業，許多運營商利用未授權頻段，通過側葉傳播的噪聲會造成很大危害。

In such cases, it is better to check the 3D radiation pattern and use an antenna with as little side lobes as possible.

在這種情況下，最好檢查一下三維輻射模式，並使用側葉儘可能少的天線。

Another view on the amount of side lobes is provided by beam efficiency.

光束效率是側葉數量的另一個視角。

Check our previous video if you want to know more about that.

如果您想了解更多相關資訊，請查看我們之前的視頻。

The 3D diagram is more difficult to obtain than the 2D one.

三維圖比二維圖更難獲得。

So historically, the 2D plots became a standard in most engineering fields.

是以，從歷史上看，二維繪圖成為了大多數工程領域的標準。

But today, with powerful computers available to everyone and advanced antenna measurement setups capable of full 3D measurement, this difference is diminishing.

但如今，隨著人人都能使用功能強大的計算機，以及能夠進行全三維測量的先進天線測量裝置的出現，這種差異正在逐漸縮小。

But let's talk about that in another episode.

不過，我們還是下一集再聊吧。

So stay tuned and if you find our videos useful, consider subscribing to our channel, like or leave a comment.

敬請期待，如果您覺得我們的視頻有用，請考慮訂閱我們的頻道，點贊或留言。

Thank you for watching.

感謝您的收看。