coaxial connector momentum

I am trying to learn how to design simple microstrip antennas using agilent's ADS. As much as i've searched i couldn't find anywhere how to design a coaxial fed microstip antenna. Do i have to use a trick or something? Because it's definitely not straightforward

I would be grateful if somebody could give me a hint.

hi,
I don't think that in ADS there is a possibilty to model a coax cable, so u have to use IE3D or HFSS to do that.

Maybe it is possible to include a coaxial connector/cable in the new version of ADS (Momentum), which has extended 3D capability. For older versions I guess it is possible, but it will probably be quite difficult to draw the structure.

Anyway, I don't think you need to include a coaxial connector/cable in your simulation. Typically, you get sufficieny accuracy by using local ports (not sure what they are called in ADS though) that you can put between the ground plane and the tip of the feed probe.

Finally, I've tried to do stuff in Momentum more times than I care to remember, and everytime I get dissapointed. The program just sucks. For instance, we tried looking at the transmission (S21) between two dipoles in space as a function of distance, expecting to see a 6 dB loss for every doubling of distance. Not so in Momentum. Below around -30 dB or so the program fails. In my view, this is simply horrible. It means there is something very very wrong with the way it solves the problem. As a reference, IE3D shows 6 dB increases loss down to about -100 dB (which is when I stopped the experiment). This is just one of a zillion bugs/errors in the program, so my advice is, if possible, to switch program.

Best regards,
Peter

Unfortunately Peter, changing software is not an option for me. I have to stick with momentum

So what you are saying, if I got it right, is to put an internal port in the desired feed point, somewhere in the patch. I'll give it a shot.

One more thing. Can anybody give me some paper titles of simple rectangular microstrip antennas, coaxial or microstrip fed? Just to verify the results i get and to be sure i'm on the right track. As much as i've search, i only found elaborate designs

Thanks again

PS I use ADS2004A

for momentum analysis you can try FEKO which do momentum analysis.further you can feed by coax.