the setting of Momentum in ADS2008_ Help From China!

Hello,everyone!
I am from China,my english is poor,so I would like to state the problem in Chinese:
现在设计一款PCB印制天线时遇到了一个问题，希望大家帮忙：我的印制天线是单层板，上面是金属层，下面是介质层，在ADS 2008的Momentum——>Substrate项中如果Substrate Layers设置为FreeSpace+FR4+FreeSpace_Bottom，那么Layout Layers该如何设置？因为我设计的是单层板，我不清楚为什么默认情况下FR4层介质下面还有“COND”？
如果在ADS 2008的Momentum——>Substrate菜单项中设置如下：Substrate Layers设置为FreeSpace+FR4+FreeSpace_Bottom，那么默认情况下Layout Layers为FreeSpace+“------”+FR4+“------”+FreeSpace_Bottom，如果我把第一个“-------”设置为“cond”，那么第二个“------”应该匹配为什么?因为我这里仅仅是单层板
请大家多多提建议，谢谢啦！
thank you!

Hello!
Can someone give me any ideas?
Thank you!


myvioletchen

It seems that no one knows how to solve this problem.....

Perhaps try the question in english

Thanks for upstairs .
Now I state the problem in English again,for my poor english ,the description may not be so accurate:
Nowadays ,I just want to design a single layer PCB ptinted antenna in ADS2008 for pleasure,but I found a serious problem——How to setup the Momentum?On my board there's only one metal layer + one substrate layer,SO if I set the button : Momentum——>Substrate like this “LayersFreeSpace+FR4+FreeSpace_Bottom”How can I set the Layout Layers?My board is single layer,but why in default there is a "cond" under the substrate "FR4"?
Thank you for your attention!I should be much appreciated for your help!

I believe you are saying that you have a single sided board. Ads 2008 substrate editor is only allowing you to specify a substrate with two sides, one of them the ground plane, which doesnt accurately represent your board.

I would recommend just setting the thickness of the FR4 substrate to a realy large value in excess of a wavelength. With a really large substrate, this should accurately represent your board.

Cheers

darcyrandall2004 said:

I would recommend just setting the thickness of the FR4 substrate to a realy large value in excess of a wavelength. With a really large substrate, this should accurately represent your board.

Click to expand...

I do not agree. Thickness of the substrate matters, and increasing the substrate thickness will create wrong results.

If the single sided board has one "empty" side, with no metal, then use a stack with free space (air) above and below the substrate layer.

Best regards
Volker

Thank you for all your help!
To:Volker,you mean that I should set the "Subatrate Layers" like this "FreeSpace+FR4+FreeSpace_Bottom",in fact I really did like this,what I concern is how to set the"Layout Layers",can you please view the image uploaded? Expecially why there is a default metal layer under FR4.

Best regards!
myvioletchen

Hai in ADS it will always take the ground layer as infinite layer.

so if u want to simulate a single layer board u have to set

Free Space

FR-4

Gnd (open) select this layer and open the ground

now u have free space and Fr-4 then add one more layer and choose Dielectric constant as "1" (for air) then it will take that as a single layer board.

myvioletchen said:

Thank you for all your help!
To:Volker,you mean that I should set the "Subatrate Layers" like this "FreeSpace+FR4+FreeSpace_Bottom",in fact I really did like this,what I concern is how to set the"Layout Layers",can you please view the image uploaded? Expecially why there is a default metal layer under FR4.

Click to expand...

Hello again,

I do not see an uploaded image?

But anyway, I think it is no problem when top and bottom metal layers are mapped in your stackup. You will only get metal on the bottom layer if you actually draw on that layer. That is the difference to the ground plane: if you assign a metal ground plane in the stackup, than you will get metal without drawing anything. But that is only if you make it a ground plane.

Best regards
Volker

To:Jamesanton,
I really did like you said,it seems that if I set the "Subatrate Layers" like this "FreeSpace+FR4+FreeSpace_Bottom,and "Layout layers"like this"FreeSpace+STRIP cond+FR4+STRIP solder_mask".The final result is good,which means the S11 can be less then -9.6dB in the BW(3dB),but the gain of the antenna is -40dBi which certainly is not so ideal,is there any way to anvance the gain?
To:Volker
It really make difference when top and bottom metal layers are mapped in my stackup,what I mean is that if I set the "Subatrate Layers" like this "FreeSpace+FR4+FreeSpace_Bottom,and "Layout layers"like this"FreeSpace+STRIP cond+FR4+STRIP cond2".then the result is so bad,S11 only to be -0.2dB in the BW(3dB) of the antenna.

Is there any problem of the setting?

Thank you for all your help!
and:
Welcome you to Hangzhou in China,It is a really beautiful city with famous west lake in it,I can be your loyal tourist guide!

Best regards!
myvioletchen

Hello! Are there any updates?
Thank you !

can u share the design?
I observe similar effect of finite gnd problems.
I guess that you assigned the layers correctly.