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【电子干货132】来自数据手册的PCB天线设计

电子干货2018-06-23 22:29:31


以下资料来自DA14580 Application note 原理图和PCB设计指导,详细文档可前往电子干货交流QQ群文件进行下载


1)DA14580 Antenna matching circuit


2)RF input and output matching

For optimal matching of the DA14580 to 50 Ohm, make sure to place a shunt inductor as close as possible to the RFIO pin. The value of this shunt inductor depends on the package.

为了使DA14580最佳匹配阻抗达到50Ω,应确保放置的并联电感(L1)尽可能地靠近RFIO引脚。并联的电感值取决于DA14580的封装。


WL-CSP package: 3.3nH inductor; both QFN packages: 3.9nH inductor.

This shunt inductor is L1 in above figure.


This matching ensures best RF sensitivity and highest RF output power.

匹配电路是为了确保最好的RF灵敏度和最高的RF输出功率。


Further, foresee some matching components for antenna matching; these parts should be close to the antenna. Most universal is a PI matching network, having two shunt components and one series component: Z1, Z3 and Z2. Type and value fully depend on the antenna type, but typically small pF caps and low nH inductor values are expected here.Maybe not all three parts are required to have a good matching. The connecting PCB trace should have a characteristic

impedance of 50 Ohm.

此外,还可看见天线匹配的一些匹配元件;这些元件应该靠近天线。最通用的是PI型匹配网络,有两个并联元件和一个串联元件:Z1、Z3和Z2。类型和值完全取决于天线的类型,但数值通常是pF级小电容及nH级小电感。当然,一个好的匹配电路,可能也并不需要三个元件。连接的PCB走线应具有一个50欧姆特征阻抗。


See picture in above.

The free Agilent tool ‘AppCad’ can calculate the characteristic trace impedances when substrate and trace dimensions are known. Also online RF calculators are available.

一个免费的Agilent工具' AppCad '可以计算出已知衬底和迹维的特征迹阻抗。还有在线的RF计算器也可用来计算。


3)Antenna placement

Whether a PCB printed antenna is being used, or e.g. a ceramic chip antenna, make sure no copper is under the antenna, and no traces are running under the antenna area. The antenna must be able to radiate freely. The ceramic chip antenna mostly requires some copper-free area around it; refer to the antenna manufacturer’s antenna layout guide.

无论使用的是PCB天线,还是陶瓷天线,都要确保天线下方没有铺铜,天线下方没有任何信号线。天线必须能够自由辐射。陶瓷天线大多要求在它周围是一些无铜区域;可参考天线制造商的天线布局指南。


4)Printed antenna example

Below the printed PCB antenna used in the Dialog’s Keyboard Reference Design is shown. The design is a so-called inverted F-antenna. One can copy and paste this design on any PCB material. Gerber files and design files can be provided.

下图为Dialog公司的键盘参考设计中使用的PCB天线。这种设计就是所谓的反向F天线。Gerber文件和设计文件可以被提供。你可以在任何PCB材料上复制粘贴这个设计。



5)Measures of the shown printed antenna:A   4 mm long, 0.53 mm wide – this is for the vertical part only

B   5 mm long, 0.40 mm wide – the antenna feed trace

C  23 mm long in total, 0.53 mm wide – the section between A - B is 5.5 mm long


The grid size in above picture is 1 mm


A PI-network for antenna matching components is provided too. Please make sure this matching circuit is present in your design. The antenna free space area should be 25 mm x 6 mm. Under and in this area there should be no ground planes, no traces and no components.

还提供了一种用于天线匹配部件的PI型网络。请确保在您的设计中有这个匹配电路。天线自由空间面积应为25毫米x6毫米。在这个区域的上及其下方应该没有地平面,没有走线,没有其它元件。


A very similar printed antenna is being used on Dialog’s new (2014) evaluation kits.

一个非常相似的PCB天线被用于Dialog的新(2014)评估套件上。

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