waveguide simulation
I am trying to simulate Quad ridged waveguide in HFSS.
Please Find attached file.
I found this example in One paper, where I got dimension & I implemented to see how it works.
But in the paper there are results which Plots graphs of S12 for TE10 mode & TE20L mode.(check attached file for images)
I don't know how to excite this modes in this waveguide & how to see results for this mode simulation.
Is there any tutorial available for this kind of simulation?
Is anyone expert in this kind of simulations?
Can any one help me?
Waiting for reply
Abhishekabs
would you please upload the paper as well.
http://ceta.mit.edu/PIER/pier79/02.0....Hassani.M.pdf
Do you know how to do this kind of simulations?
Hi,
Did you find solution to my problem?
I have added the link for paper.
Hi!
your simulation setup should be changed I guess. Please remove the radiation airbox (and boundary), perfect E boundary (over the waveguide) and may be you can change the aluminium to PEC (not important though). Moreover, when you define the waveport, increase number of modes to at least 4 for both ports. Now simulate your structure and you can see the results you expected.
I simulate the same structure in CST and it gives the same results as shown in the paper, however, results from HFSS are little bit different.
regards,
shameem
How to increase number of modes?
& how to see outputs of different modes?
when you define the integration line, you can see on the top: modes. just increase the number to 4.
just as you see normal output: from results (rectangular plot)
As you saw in the pdf that the quadridged horn antenna has two probes to receive dual polarized signals, how to do this in HFSS?
Suppose you insert two coaxial probes as shown in that paper, how to asign two different polarization?
Means how to excite?
Suppose I want to make quadridged horn for 1-3GHz bandwidth, do I need to consider all modes?
Since you use the coaxial probes perpendicular to one another you have already two polarization!
nothing special. just draw the waveports at two coax.
In the paper, they only use single mode (other modes are not propagating). you can design your system just like that.
Ok. I thought you have to mention during making waveport that signal is polarized.
Since there is option "Polarize EField" in Mode menu.
But I was not sure whether to use it or not.
Added after 2 hours 25 minutes:
Hi
My question may sound stupid.
But I saw in one tutor that you make a rectangal with material air & assign sides of that box as perfect E or with finite conductivity & assign upper & lower part as a waveport.
This is how you form waveguide in HFSS.
And I made sides with finite conductivity by assigning aluminium. Is it correct?
[/quote]
Please see the attached image.
I want to see S paramater of different modes for waveguide with one waveport & other end closed.
I am not geting the numbers they have assigned.
How we will come to know that the mode you are plotting is TE10 or TE20 etc?
In the paper, they plot the S21. Therefore, closing other port will not give you the S-parameter curve. If it is shorted, there would be very high reflection from the other port. Just put two waveports and assign 4 modes for both ports.
You need to take a look at the port modes. From the field at the boundary, you can tell about the modes. However, I told you earlier, the S21 shown in the paper are not same what you will see in HFSS (CST gives the same result).
select S(Waveport2:1,Waveport1:1) to have transmission of first mode from waveport1 to waveport2. check all S(Waveport2:[n],Waveport1:[n]), then you understand what it is all about.
Hellow shameemkabir,
Thanks for your help & kindness.
I was finally able to validate model without errors. :D
Also did this kind of horn simulation first time. :D
I have two doubts for this quadridged horn simulation.
1) The 2 output ports should be defined as lumped or waveport?
Actually there will be SMA connectors in practise I guess.
2) I was able to find out how in that paper ridge height & impedance has been derived from the formula. ( For so many days I was thinking this formula is for ridge drawing )
But I am stuck with actual ridge drawing. Should we use any equation or use polyline to draw? what will you suggest.
BR,
Abhishekabs
Added after 53 minutes:
Please check your personal messege.
I have attached the hfss file. Please suggest me.
If you draw the coaxial feed with correct dimension, it generally does not matter whether you use lumped port or waveport (in both cases, the impedance would be 50 ohm). Moreover, a SMA connector is nothing but a 50 ohm connector. Therefore, no need to simulate with SMA in this case.
you can use equation to draw the line (like it is used in Vivaldi antenna design). one axis would be fixed, one axis would be changed according to variable (_t is this case) and other axis would be changed in exponential form e^(kx) where k is a variable you set to get different taper.
Hi Shaameemkabir
by any chance do you or your friends have access to this paper?
K. L. Walton and V. C. Sundberg, "Broadband ridged horn design,"
Microwave J., pp. 96-101, 1964.
I tried everything to find this article. but I did not get it.
Hi Abhishekabs!
why don't you write a mail to Microwave Journal directly to ask for this paper?
I did. but they did not send me the paper.
They asked me to register & I did. but they did not sent. thats why I am requesting here. :(
Hi sirs, I have the same problem. Have should I draw the integration lines. Could you post an image about it (i.e. paint work).