UWB Antenna using IE3D - results difeerence

UWB Antenna using IE3D

Hi all,

I`m trying to simulate an UWB antenna from an IEEE article using IE3D; but I have some problems. The result of the simulation is not the same as posted in the article.

I am not quite sure of what's wrong with my model. I have attached the IE3D simulation file and the accompanying results.

Can anyone offer some suggestion to solve my problem?

thanks and best regards.

UWB Antenna using IE3D

I will take a look at your IE3D file tonight and see if I can see anything wrong.

Re: UWB Antenna using IE3D

Thanks b4bb4ge!

UWB Antenna using IE3D

You know for the life of me it all looks fine maybe the paper is wrong?

Re: UWB Antenna using IE3D

hi b4bb4ge,

I discussed with my friends, and they also have no idea what's wrong with my simulation.

I don't suppose an IEEE paper could be erroneous. Perhaps i interpreted something wrongly from the paper? Could you help me take a look at it?

Thank you so much for taking time out to help me out...really appreciate it...

Re: UWB Antenna using IE3D

Hi:

I would like to make a few comments on this structure:

The gnd is very small compared to the patch. I am afraid there is a significant inbalance between the patch and the gnd at the feeding point. The inbalance may cause much uncertainly in the results, no matter whether measurement or simulation is concerned. This is a similar situation when you try to meausre a dipole antenna with the 2 arms not the same length or you are using a coaxial to feed a dipole without any balun. In the reality, the current will go onto the outer surface of the coaxial feed line and become part of the radiator. If you measure the impedance, depending how you feed the antenna, you will get different results because the feed line is part of the antenna. I think it should be one of the most significant source of error involved.

Some users discussed with me on matching the measured results and simulated results for CPW fed antennas. It is the same problem. They didn't make sure the feed is balanced between the positive arm and the gnd of the antenna and it introduces all kinds of uncertainly into the measured or simualtion results. If the structure is symmetrical such as symmetrical dipole antennas, or the positive arm is significantly smaller than the gnd (monopole on a big piece of gnd), the feed will become well balanced and you will get more consistency between measured and simulation results. In case you have a unbalanced structure, you should need to take some measure to make sure what you are simulating and what you are measuring a consistent. If you don't get good match, it is quite likely due to the setup of your measurement and the setup of the simulation are not consistent. Regards.

Added after 8 minutes:

More comments on the simulations:

1. You don't need to choose so few frequency points for such a simulation. You can define the frequency range from 1 to 15 GHz with couple hundred frequency points for smooth results. It will slow down much.

2. If you choose the Contemporary Meshing, it will reduce the meshing and you will get faster results.

3. If y ou can divide it manually or use the Adv Edit->Rectanglization to divide into more rectangular shapes, you will also be able to speed up the simulaton much. Anyway, as it is, the speed is quite good already. It take a few minutes on a good computer to run. Some simple revision may make it better.

Added after 10 minutes:

Sorry. I had a typo in the additional comments.

Putting couple hundred frequency points will allow you for smooth results without slowing down the speed. You will accurate results in about the same time as long as you use Adaptive Intelli-Fit (AIF). Regards.

UWB Antenna using IE3D

I totally understand.

Your simulation is right. But sometimes, junk Antennas were published.. especially in other contries.
I also had lots of same situation. I simulate several UWB antenna, which size is really small (length is less than 25 mm)
I finally conclude if antenna size is really small such as less than 25 mm, I will not believe their publication.

Re: UWB Antenna using IE3D

Hi,

so sorry for the late response... i am so new to antennas, spent the time reading up

Thanks jian for the comments.
Was wondering if IE3D can accurately model the coaxial probe using the "probe-feed-to-patch" function? the function only models the inner conducter if i am not mistaken, and to me it seems to be in direct contact with the ground plane, whereas in the real case there should be an outer conducter that is touching the ground plane?

yeah, kenny44, i used HFSS to run the simulations and got the same erronous results... wanted to contact the authors but couldn't get hold of their emails

Re: UWB Antenna using IE3D

I totally agree with KENNY 44 's opinion and comments on some papers from other countries . Please find the attached paper, Can your guys can repeat the claimed results in the attached paper ?

Re: UWB Antenna using IE3D

kenny44 said:

I totally understand.

Your simulation is right. But sometimes, junk Antennas were published.. especially in other contries.
I also had lots of same situation. I simulate several UWB antenna, which size is really small (length is less than 25 mm)
I finally conclude if antenna size is really small such as less than 25 mm, I will not believe their publication.

Click to expand...

Do not expect the research paper will give you all the detailed information for free, especially for something that can be patented or used for business applications, if you have questions you should contact the person who published the paper for details. Most of the response I got is they can not disclose the details because the funding is provided by some organizations. the paper is just to disclose what they have done, not the details. this is true if you try to access to the NASA search info. (as disclosed in NASA tech. brief) you have to pay first. even though they are funded by the tax money of general public.

Most of the university in other country do not disclose the master's and doctor's thesis now-a-days, especially for new technology research and can be used for business applications, they spend 5 years in research and want to get some return from it before you and I can use it for free. This is fact of life.