HFSS--probe in waveguide transistion

[zfeiyu]

I'd like to build a waveguide transistion with a coxial line feed in HFSS. But I am not sure how to construct the models.

how can i put a excite wave port in the waveguide? I try to subtract a circle(wave port) but it seems not correctly.

can anyone upload a easiest model of a probe waveguide transistion? I just need a example.

Thanks very much

 

[kecbackbencher]

Draw a circle at the coax input and than assign the port
draw the coxial connector as per dimensions

SMA connector= 0.65mm inner dia , 2.05mm outer dia, teflon between

N Female Connector= 1.45 mm inner dia, 4.85mm outer dia, teflon between

during subtraction, keep clone the tool part the body under subtraction

Hope this helps

kecbackbencher

 

[zfeiyu]

thanks very much kecbackbencher
should i build the 3d model of the SMA connector? I read a tutorial about a microstrip antenna feed and it showed a way: just draw a circlea and a cylinder set this circle as lumped port excitation and the cylincer as the copper pin, then it said it was a simple coaxial waveguide feed exciting.

So I built a box, set 4 faces boundary as copper, and draw a another rectangular overlap the bottom face of the box, then subtract a circle (also clone it)on the rectangular and set this circle as lumped port excitation.

Did I do correctly?

In addtion, I want to build a waveguide transistion as an antenna function, so I left one face of the box(waveguide) as vaccum and built a air box outside the waveguide. Am I right?

regards

 

[kecbackbencher]

No need of making whole SMA connector, you are doing electromagnetic analysis of SMA connector, just make inner conductor of dia meter 1.3mm and out conductor diameter 4.1 mm with teflon in between.
insert it in the rectangular waveguide from the middle of broadside from Lambdag/4 distance from the short ( actual point is somewhat less than lambdag/4), the SMA connector pin is soldered with extra length with some steps and pin head at the end that behaves like a monopole antenna and convert the TEM mode of coax to TE mode of tectangular waveguide. this pin depth, position from short and the step radius are the tuning elements. By the way, which waveguide to coax trnasition you are going to design.

 

[zfeiyu]

Thanks kecbackbencher

I want to build a waveguide working at UHF frequency, around 866mhz.

I got the s11 was extremely low (-0.005db). do you know is there any tutorial about HFSS in waveguide transistion

 

[kecbackbencher]

I think you should go for WR1000 is appropriate for your frequency , use N female connector rather SMA because size of waveguide is too big

Added after 1 minutes:

I think problem is at the feeding point. wave is not able to propagate g=freely in the desired path

 

[fyp05]

Can anyone tell how to make an N-type connector in HFSS? What would be the dimensions? What would be the material assignments?

 

[tony_lth]

Draw a circle at the coax input and than assign the port
draw the coxial connector as per dimensions

SMA connector= 0.65mm inner dia , 2.05mm outer dia, teflon between

N Female Connector= 1.45 mm inner dia, 4.85mm outer dia, teflon between

during subtraction, keep clone the tool part the body under subtraction

Hope this helps

kecbackbencher

He has already written the dimensions about N-type.

For the probe in waveguide transistion, the waveguide port should have some ladder to get very good VSWR and wider bandwidth. Agilent first did it.

 

[MobiNaz]

Could you please explain, how to design the wave guide, that is design only the vaccum portion, with finite conductivity assigned to five faces except the one which is feeds the waveguide (assigned as waveport).

How do I verify that the waveguide is tuned to the required frequency by looking at S11 parameter?


Thanks in advance

 

[elchiquito]

Hello MobiNaz

There are plenty of literature available about waveguides in hfss.You should probably look into this one.if in case you havent had a chance to look at it

https://www.rit.edu/kgcoe/eta/docs/Project-1-HFSS-tutorial-Rectangular WG.pdf.

If you need any assistance please feel free to let me know.i will defintely extend my assistance

Regards
ChachitoEL

 

[asgant]

hii kecbackbencher..
i want to model waveguide to waeguide transistion using coax..
first what i did is ..i modelled waveguide to coax transistion..im confused how to model coax that gets into waveguide..the e-field is not transfering into waveguide..i think the problem is with coax only..could u pls tell me how to model it..
thanks in advance