Ports in SMA connector in CST

isolated sma connector

I have modeled an SMA edge board connector in CST and I want to simulate its E field, S-Parameters, etc. Where and how should I connect the ports? My model includes the pcb, ground plane and a microstrip line connected to the inner part of the connector (see attachment). Where do I place the ports? what kind of ports? any simmetry planes? Do I need a so-called "capped port" (I don't know what it is)?

**broken link removed**

Thanks in advance!!!

cst distance to ref. plane

Take your model and connect to it another sma in the other side of the microstrip
Put WG ports on each SMA then choose in MONITOR menu the E field in the freq. you want.
In the boundary put magnetic sym. in the axis that pass thru the 2 SMA and the microstrip.

You can add the solder by blend between the pin and microstrip.

RGZ

cst sma

Thanks for your reply. Where exactly do I place the ports? On the most outer face of the inner cilynder of each SMA?
About the parameters of the waveguide port:

- Normal to X, Y or Z? I supose it must be normal to the axis of the SMA cylinder.
- Orientation Lower or Upper?
- Coordinates: Free or Full plane? This gave me problems while trying to solve but I don't understand the difference.
- Multipin port? Number of modes? Distance to reference plane?

I have modeled the solder as you can see in my other attachment. In order to let CST understand that the cylinder and the microstrip are in contact, I have merged their shapes so that just one component exists, is this correct? Should I merge the body of the SMA with the ground plane component?

Many thanks in advance for your help.

Added after 1 hours 27 minutes:

I can post pictures of my simulation or even the whole simulation if someone needs it, and we can work on it together. If someone is interested just reply this post or PM me.

Added after 6 minutes:

All my results are zero! I mean, all the E-fields, power and everything is zero all over my model! I don't know what I am doing wrong, please help!

sma connector microstrip

pepillo said:

Thanks for your reply. Where exactly do I place the ports? On the most outer face of the inner cilynder of each SMA?

HI Pepillo,
I have simulated microstrip to sma transitions and I put the waveguide port on the sma doing the following:

- Select the surface of the dielectric in the sma connector with "pick face" button (pick face.bmp).
- After slection press the waveguide port button and the waveguide port is automatically added to your sma connector (pick 2.bmp), in your desired direction. I have had no problems doing this

I hope this will help you
regards

Click to expand...

face ports + cst

Dear dch316:

I have already tried this but I didn't pick the face on the dielectric of the sma, instead I picked the face of the inner conductor of it and I placed the WG port using this pick. Is this wrong? Must I place the port in contact with a surface on the dielectric? I thought the signal entered the device from the inner conductor.

By the way, I am spanish too, maybe we can exchange knowledge, where are you from? I am studying electronics engineering right now, and I am working on microstrip and sma simulation, if you are interested in exchanging information please PM or email me.

cst sma microstrip

pepillo said:

Dear dch316:

I have already tried this but I didn't pick the face on the dielectric of the sma, instead I picked the face of the inner conductor of it and I placed the WG port using this pick. Is this wrong? Must I place the port in contact with a surface on the dielectric? I thought the signal entered the device from the inner conductor.
.

Click to expand...

hi again,
The signal in a coaxial line is defined by the E field in between the two conductors, that means that the voltage inside the inner conductor is 0 (pec) and the voltage inside the outer conductor is also 0.However there is a difference in voltage BETWEEN those conductors. Therefore, to create a wave in this line you have to create a different voltage between the outer an the inner conductor, so the wg port should cover at least a portion of both conductors. That might be the reason everything is null. It should work too picking the normal face of the outer conductor.By the way, which boundary conditions did you set?

regards

cst sma connector

Ok I'm gonna try to set the port picking the face of the outer conductor.
I also get many other warnings: "the solid component1:solid5 (the outer conductor) touching the open boundary at Xmax has very high losses. The accuracy may be degraded in this case".
Boundary conditions: magnetic symmetry around plane XY (along the microstrip line and the two sma), as I was told by Plasma.

Added after 15 minutes:

Now I have placed the port on the outer conductor, I can see some E-field on my model but not much, almost unnoticeable... I'm not sure this is correct. I wonder if the problem is in setting up the contact between the strip and the conector, because I also get the S-21 and S-12 almost zero, as if they were isolated, but they aren't! The structure is pretty simple so I don't know what's the problem...