how to set the output port of micro-strip balun in hfss ?

i have some problem about this question ,i hope somebody can help me .it is a balun for sprial antenna ,but i do not want to simulate the balun with the antenna ,also i do not kown how to set the output port in hfss . plz help me !

hi hausan,
i have simualted balun separately by using wave ports at two end of balun ,mine was microstrip to slot line transition so i used 50 ohm wave port at microstrip line and 120 ohm at slotline side. i think you can try it for yours

i kown what your mean ,but i do not how to set the port? lumped port or wave port ? i have try the lumped port and the wave port but the result is not ture .could you post the screenshot of the ports ?

plz ,if you can post the model of the balun ,i will be more happy .

for wave port setting you should take a reactangle of size 4*h(where h is height of substrate) and 5*w(width of microstrip line) using wave port option from assign excitation of hfss.then either you should make a box of material pec joining wave port rectangle or you can draw a radiaonton box touching wave port rectangle .in this way you can built a waveport to any system. i have attached pic of port but its not very clear

i try with your advise ,but has a alarm : internal face can not use wave port ?

well when we use waveport we must either do build a radiation box in such a way that its one surface touches wave port. the warning you are telling is because of that.you can eiter build radiation box in this way or you should build a box of same size as that of wave port and assign that box pec amterial then you will not get this msg

thank you .the alarm is disappear.

hi aniakhan
i want to send my project to you ,could you help me check it ?

what you want to check? i can open it prpoerly as i have hfss 12 now not 14 so u can post your results in simple ppt here to talk.


also another thing if you have some question about antenna then post it on n RF, Microwave, Antennas and Optics forum of edboard because normally people don't saw em simulation portion therefore not possible to get answer soon.

thank you ，my friend



i care about the ports set,i should ensure it is right,or it will effect my other work.

normally if you assign a specific impedance to wave port at end of wave port assign procedure then its dimensions will not matter but normally wave port should be of diemsnion 5*w and 4*h. one thing if you know is i have made transiotional structure as balun previously but now i am interested in exponential tapering of Microstripline i know formula for tapering of M/s line and exponet factor as well but i am not finding exponet factor for ground plane tapering ,if you have any idea please tell me.as yours was k.balun so i thought may be u know..

hi ,aniakhan
i am a greenhand of this field ,i have to learn some kind of balun .but nobody around me do this ,so i have to ask for help.if you have some model you can send it to me .with my deeply thanks

i have not worked on many baluns but i will try to complete exp balun and then attach model here soon.

thank you ，my brother！

hi,aniakhan
i make a balun like the tapered balun ,and the result of the simulation seem well. the ports set are according to your suggestion. can you check the model ,i need your support .

hi,
i have lower version of hfss and it is not simulating in my system because of some software problem,why dont you make a ppt having all results like s11.s21 and s22 and image of your balun??or attach them in fig format i will have a look and tell you.

i have make a ppt .

well your results are correct as far as S11 and S22 are concerned having value below 15 .do you have to connect it with antenna??if yes then any antenna with RL less than 15 will do good with it. but S21 is not good it should be maximum 1 db otherwise when conect with antenna less power is transmitted. so try to improve it. i have seen your model in hfss you can also use lumped port for port why have not you used them??although it does not matters more but lumped ports are easy to use. for lumped port just use any rectangle of any size and give it lumped port
do you have any paper related to such type of tapering??? how did you manage tapering constant (its for my curiosity)??

i find a paper in google .
Design and implementation of wideband baluns for Archimedean spiral antennas
http://eprints.qut.edu.au/49773/1/Ka...thy_Thesis.pdf
i hope it can help you with you study.

hi aniakhan
could you point some key problem of the design tapered balun ,i am not clear of the part ,but someday later i have a chance to ask the expert ,i would not like to lost face !!plz