Help! Dual band 2.4GHz/5.4Ghz monopole antenna

[guo-hai]

Hi,
I'm a newbie for the antenna things...
and i get this for my final year project..
My professor give me the sample of the antenna(substrate FR4 with Er=4.4 and thickness ≈ 1.6mm )... i measure it and simulate it with HFSS..but the result i get is just at 2.4GHz.. no loss in 5.2GHz...
i tried to modified the design , but still don't get it...
i'm stuck in here..
can anyone help me please?
this ismy design picture and simulation data...

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Thank you before.

 

[ferdows]

hi did u attach the whole of HFSS ????????? PLs send only the main file !!!!!!!!!!!!

 

[mitch81]

before the modification of design, did you choose a good dimension for your radiation box? LAMDA/4 minimum. also boundaries conditions are very importants...

 

[guo-hai]

Thank you for replying,
i use the PML setup wizard... my professor ask me to set it about 150mm big...
and how to calculate lambda, is it using this formula? ( lambda = c/f)

OPs, sorry, i don't know... hehehe... this is the main file..

 

[ferdows]

hi
i send bowtie antenna but i choose taconic RF-35

 

[zorro]

Hi guo-hai,

..but the result i get is just at 2.4GHz.. no loss in 5.2GHz...

What do you mean?
Regards

Z

 

[guo-hai]

hi ferdow.. is it dual band on 2.4Ghz and 5.2 Ghz?

hi zorro, i don't know how to say it clearly, i mean that the result from the analysis.. the s parameter i think... i got 2.4 Ghz in about -30db, but i got about -4 db nothing in 5.2Ghz...

---------- Post added at 11:48 ---------- Previous post was at 11:47 ----------

hi ferdow.. is it running on 2.4Ghz and 5.2 Ghz?

hi zorro, i don't know how to say it clearly, i mean that the result from the analysis.. the s parameter i think... i got 2.4 Ghz in about -30db, but i got about -4 db nothing in 5.2Ghz...

 

[ferdows]

hi
yes its a dual band at 2.4 and 5.2GHz

 

[zorro]

...i mean that the result from the analysis.. the s parameter i think... i got 2.4 Ghz in about -30db, but i got about -4 db nothing in 5.2Ghz...

So it is s11: -30 dB (good matching) at 2.4 GHz and -4 dB (bad matching) at 5.2 GHz.
Can you show a figure of s11 over a wide band (e.g. from 2 to 7 GHz)?
Regards

Z

 

[mkonca]

I simulated the antenna again and the structure does seem to resonate only at 2.4GHz but then I use a wave port which I think handles multiple resonances better than lumped ports. As a result I got a resonance at 5.8GHz as well as 2.4GHz.

 

[zorro]

Good!
Mkonca's results show that the lower resonance is, as wanted, at nearly 2.4 GHz but the upper one is higher than wanted.
In order to tune this resonance at 5.2 GHz, the notches should be displaced. As a first approximation, I'd increase the distance between them by a factor 5.8/5.2, i.e. about a 10% increase.
Fine tune of both resonances can be obtained experimentally by judicious iterations.
Guo-hai, why the drawing is slightly assymmetrical?
Regards

Z

 

[guo-hai]

actually, i still don't understand about antenna ... all i do is learning how to use the software and copy the sample drawing..
THanks mkonca...i will try using wave port... =D
zorro, i dont really understand what you mean above...
ANyway... do you have any reference (book, ebooks or website) that i can study to understand antenna easily?? =D

 

[guo-hai]

i have tried using wave port.. i analyzed it, but it stopped.. it said that port refinement, process hf3d error. port 1 is assigned into internal face. Only allowed with lumped port....

 

[zorro]

Hi guo-hai,

you should, at least, understand the priciples of atenna resonance and matching, anh how a dipole works.
There are many good books, e.g. Balanis', Stutzman and Thiele's, etc, that cover almost all about antennas, including dipoles and printed antennas.
Try to learn about the above mentionned subjects.
Regards

Z

 

[guo-hai]

THanks zorro.