how to give waveport and air box for monopole antenna in hfss

[dreamzalive]

thanks a lot for your guidance and help..
actually, i solved this problem in ie3d in which i have taken the feedline of 3mm for which the result was coming perfect that's why i was trying it on hfss with the same dimension,
and while i was using waveport the impedence was 36ohm, so i gave the lumpedport impedence of 36ohm. i did it on rt-duoroid and am getting the prfect result and simulated the same for fr4 but as you said the third notch was not appearing so i wanted to know that my design was correct or not.i also changed the dimensios a lot than i asked here.if you want to see the rt-duoroid result ican upload that here.and the file you have sent is not opening, something called line render axis error is coming and hfss11 is not able to read the i/o.

 

[sweetchoto]

Hi,

I have Hfss 12.1 that is the reason you are unable to open it. I dont have HFSS v11 so i dont know how can you open my file without hfss v12.1 or higher. You can upload the project with RT-duroid but again any change i will do/make you wont be able to see it as you have hfss v11. Why dont you upgrade to V13? My suggestion try with microstrip feedline width of 2/1.9 mm and then see if it has any effect on the results. I have corrected your AirBox dimensions aswell so make sure that your AB is 25mm away from each side. Even with 3mm feedwidth first 2 notches are at about at the same frequency ranges where expected and 3rd notch is not appearing due to the same reason which i mentioned before and that is my opinion which can be wrong/right. I dont know much about IE3d tool never used it but i have used HFSS extensively and i trust on its results.

/SC

 

[dreamzalive]

could you please tell me how to get hfss13.

 

[sweetchoto]

Contact HFSS technical people for upgradation of your license.
/SC

 

[dreamzalive]

i want to find gain at each ffrequency from 3-11ghz. can we plot the graph between gain and frequency in hfss as i am getting gain only on central frequency for which i am simulating the structure at different angles..please tell me how i can get gain at each frequency in one simulation in hfss..

 

[ferdows]

hi
no it impossible for your antenna because in CPW antenna u have not one beam with constant direction better u find it for each frequency like 3, 4, ..,11 and then plot them by matlab or excel

 

[dreamzalive]

εreff=(εr+1)/2+(εr-1)/(2sqrt(1+12h/w))
l=λ/2=c/(fc(2√εreff))
εr=relative permittivity
fc=central frequency
this is the formula which i used to get the lambda and my lambda/4 was coming 12.25mm but you told it should be 25mm.
which formula you used plz tell..

 

[sweetchoto]

Hi,

For the Air BOx dimension, Lamda is calculated by the simple formula of C= f*Lamda,where C=Speed of light and f= frequency(always choose lowest frequency of interest in your frequency range).

There is no point in using er(relative permittivity) in calculating Lamda for Airbox dimensions since we are interested in seeing the behaviour of emwaves(coming out of antenna) in free space(far-field region). The formulae you have written it includes the factor of er=relative permittivity(for air it is 1) and there is no point to calculate lamda on the basis of it.

Your second question about gain vs frequency. No matter what kind of antenna you simulate in HFSS you can always plot gain vs frequency. just follow the following steps:

Hfss-->Results-->create farfield report-->Rectangular plot

New window will open up

In solution tab:Select your frequency sweep(By default it will be Last adaptive and that is why you only see gain at centre frequency only)

Primary sweep tab: Freq(by default you will see theta in it.when you will select freq all frequency points in your sweep will be automatically selected.)
Category tab: select gain
Quantity:select Total gain
function:dB

Click families tab: Select appropriate values of Theta and Phi in which direction you want to see the gain of your antenna.

just click New report and you will get your gain vs frequency plot as you desire

/SC

 

[dreamzalive]

Hfss-->Results-->create farfield report-->Rectangular plot

New window will open up

after the the option of frequency sweep is not coming, only last adaptive option is there...
what to do??

 

[dreamzalive]

should i upload my project again or canu you plz check in previous projects??
only last adaptive option is there in the scroll down window.., what to do??

 

[ferdows]

hi whats u problem now pls upload u last effort

 

[dreamzalive]

hey,i have attached the latest project. actually i want to find the gain at all frequency in one simulation. i tried to do as was suggested above but after

Hfss-->Results-->create farfield report-->Rectangular plot

New window will open up

in this i wanted to do frequency sweep instead of last adaptive but in scroll down menu no other option is coming, only last adaptive option is there.. so plz check it how to get frequency sweep there..

 

[ferdows]

hi dear
i said u one time for CPW structure its wrong u calculated gain by discrete simulation because in this antenna pattern change by increase of frequency with that method u can find gain in constant theta and phi so better for simulation and design gain for some frequency and plot them in matlab usually done this work papers