Question about waveport in HFSS

[burton]

Deal all,

I am simulating a filter with 50Ω microstrip as input/ouput (Er=2.2, h=1mm,w=3.11mm, Fre=9-11GHz) in HFSS. According to the rules, the width of waveport is about 5w and the height of waveport is about 4h. However, the dimensions of the waveport exceed the lambda/2, which permits the TE10 retangtular waveguide mode excitation. If the dimensions of waveport are deceased, the field distribution of port becomes bad and the impedance of microstrip is a bit smaller than 50Ω (46Ω).

What should I do? If I choose only one mode in waveport setup, do the high order modes have effect on the simulation results?

Thanks in advance!

 

[maverick09]

Well thats the tricky part.........i guess one of the right way to check for right port size is simulate first for port only solution and verify the fields.......if you see the the right field distribution....then the port is right.
hope this helps

 

[cvenkat]

i think selecting one mode in setup shud work...anyway i'll also simulate and wud like to discuss..

Added after 46 minutes:

hi,
I hope this shud work. (sorry if the idea is very naive. im new to HFSS and RF ). extend the strip with shorter width, define port and DEEMBED the extension.
thanx...im keen for ur results.