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dyq7
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PCB antenna

Dear Dialog Team,

We are trying to leverage the antenna introduced in AN-B-027 design for our project based on DA14585, but we have few queries:

1)Why is there a trace at the bottom layer of the antenna too and why are there vias connecting the top and bottom traces of the antenna? 

2)Noting that the parameters of the antennas in the AN-B-027, dxf format antennas, and DA1458xPro development kits are not the same, I used Ansys (HFSS) to model the antennas in the AN-B-27, made impedance matching in ADS, fine-tuned the impedance matching parameters, and the waveforms were different from the AN-B-27, and I didn't know what was wrong.

 

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Martin.Ge
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Joined: 2020-01-06 06:51
Hi dyq7,

Hi dyq7,

1)Why is there a trace at the bottom layer of the antenna too and why are there vias connecting the top and bottom traces of the antenna? 

Which RF desgin examples in the document are you referring to? For some examples of antenna design, the antenna is implemented on top and bottom layers and stitched together using vias. 

2) Could you pleasae clarify your question? Which design examples are you comparing to? 

And if you are modeling the RF performance, please make sure your matching network is desgined correctly.

Br

Martin

dyq7
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Last seen: 1 year 5 months ago
Joined: 2020-03-27 11:53
Dear Martin 

Dear Martin 

1)Why is there a trace at the bottom layer of the antenna too and why are there vias connecting the top and bottom traces of the antenna? 

I refer to the full size printed IFA (figure 3) in AN-B-027  and wonder why the antenna is implemented on the top and bottom layers and stitched together using vias, and  What antenna parameters can this implementation improve ?

2)  Which design examples are you comparing to? 

I compared three examples : full size printed IFA(figure 3) in  AN-B-027, ant_ifa.dxf in an_b-027_designing_printed_antennas_dxf.zip , layouts of DA1458xPro development kits, the parameters (L,H,etc. ) in these examples is different. So I used Ansys (HFSS) to model the full size printed IFA(figure 3),and made impedance matching in ADS, If the same component in Figure 4 is used , I cannot achieve impedance matching in ADS, but the adjustment element impedance is matched,  the waveform trend of return loss is not the same as that in Figure 5(AN-B-027)。

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Martin.Ge
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Last seen: 1 year 6 months ago
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Joined: 2020-01-06 06:51
Hi dyq7,

Hi dyq7,

1) why the antenna is implemented on the top and bottom layers and stitched together using vias, and  What antenna parameters can this implementation improve ?​

The reason that in this example, the antenna is implemented on both layers is the folded versions can reduce the space requirements by half and still achieve 100 MHz to 150 MHz bandwidth, which is enough to cover the Bluetooth low enegy 2.4 GHz band (at -10 dB return loss).

In this way of design, it save the design areas and still has a good radiation performance. 

Other parameters to improve this implementation is that: you can change the length of the antenna, the typies of antenna. The premise is that you have a good match of impedance

2) the waveform trend of return loss is not the same

In your document I found that the parameters you choose is not the same as it shown in the example. That might be the reason why you cannot get the same results as the example shows. 

Br

Martin