Can any one please suggest me the procedure for applying FDTD or FEM (or any other) method on modelling of a rectangular/cylindrical shape (3-dimensional) antenna as well as to get other parameters like bandwidth, radiation pattern etc.
Thanking you.
That is a very big question! Here is the shortest possible answer I can come up with...
Are you wanting to use a simulation software or write your own codes? I have a list of open-source software for EM simulation at the following link. Just scroll down to "Electromagnetic Simulation Software."
http://emlab.utep.edu/opensource.htm
It sounds more like you want to write your own code since you mentioned specific methods. You may want to check out the following link which provides and describes a method of moments code in MATLAB for antennas:
http://ece.wpi.edu/mom/
Between FDTD and FEM, both have advantages and disadvantages, but I think you will have your code working sooner with FDTD and there are more resources on the internet to help you. You will first need to learn the method. Second you will need to set up your code properly in order to simulate the antenna. Assuming you understand the method, here are the basic steps for FDTD:
1. Create a grid large enough to fit your antenna, a PML probably on all sides, and a quarter to half wavelength of space between the antenna and PML.
2. Assign material properties to each point such that it looks like your antenna when your visualize the data.
3. Figure out a feed mechanism, but a simple gap source will work in many cases.
4. Excite the antenna with a broadband impulse using the TF/SF method so that you can record the reflected signal.
5. Record the reflected signal and also the waves at the boundaries of the problem.
6. If you FFT your reflected signal you will see your S11 (reflection) vs frequency. You can determine FWHM bandwidth from that just from width of the dip in this plot.
7. You will perform a near-field-to-far-field (N2FF) transformation around some closed surface enclosing your antenna. From this you can calculate the vector radiation pattern.
Here is a link to a course I teach on FDTD that should get you started in FDTD.
http://emlab.utep.edu/ee5390fdtd.htm
This does not cover antenna analysis or NF2FF transformation yet, but you will understand much of what I wrote above. There is still more to the simulation than I mentioned like meshing, convergence, etc. You will get a feel for all of these from the course above. All lectures are on YouTube and in electronic form.
Hope this helps!
Of Course its a very big question.
You can also see following paper for further details.
http://ieee.rackoneup.net/rrvs/10/Finite-Difference%20Time-Domain%20Method%20and%20Its%20Applications.pdf
This may sound obvious , if you are using Maxwell's equation for design then formulate the equations and use FDTD/FEM solvers. (FDTD has been used with EM fields).
Again basics: Conductivity , 𝜇 and 𝜀 of the material are critical aspects that translates to geometry (for E & H scattering and /or absorption)
Thank you very much Raymond_Rumpf sir, for your kind suggestive and technically beautiful lines. Actually I want to write own codes,indeed given information are very much helpful.
Thank you again.
Sounik Kiran
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