UWB antenna & BALUN

vivaldi antenna

hi,

first i have some questions about the purpose of wideband antennas? is it possible to built a dipole that has bandwidth more than an octave? can u tell me the frequencyranges? (GHz is preferred). What are the conditions for resonance for dipoles ( working with capacity(C) and inductivity(L))?

but this is more important for me to know !!!

i have to built a vivaldi antenna( 3.1GHz -10.6GHz), i found good stuff on this board, but im not sure how to match the microstrip to the coaxcable.
is it possible to put a balun on the planar material (FR4)? How does it look like?
do i have to care about the bandwidth?

where can i find baluns when it is not possible to put lumped elements or microstrips directly on my platine? (any websites selling baluns?)
what about a direct match (sma connector), do i have to many losses?

it would be kind if u can help me and try to explain the match with some pics and values, cause it is easier to understand.

vivaldi .hfss

Hmmmm. You seem to be thinking about these antennas in the "frequency domain". I suggest that you think about them in the "time domain". Especially, what does the antenna do to an impulse or step (integrate, differentiate, etc).

балун для антенны

If you do the pcb balun, the size of the pcb is quite large. It is practical for the research field. However, it is not practical in the product view because of the large pcb size of the balun.

uwb balun

what do u think about matching with a wilkinson splitter, so i can force the system to 50Ω.

i heard that there is a big problem with the bandwidth if i wanna use a balun, is that right?

what do u mean by time domain and frequency domain; im not sure yet but i think i have to use the time domain... why you were asking me, what do i need to mention for my testings?

balun uwb

The capacity and inductivity character for antennas are due to the frequency.

Dipoles display capacity in low frequency and inductivity in high frequency .

www.rdfwt.com

browse after register.

hi,
i found an antipodal vivaldi antenna to solve the balun prob they use taper. it works pretty good.
i built an antenna and was using eagle it was pretty tough to get an exp-function.

i start using hfss... i heard you can use exp- functions, i didn't find it, i working with hfss 9.2.

another question is if i can print the model. of the top side i need a mirro view and the bottom can be leave as ist is.

on the hfss_full_pdf i found a cpw bowtie, does anybody know where i can find similar explinations for vivaldis? cause i don't know waht to use like ( driven modal or driven terminal), the only material i have is FR4 and the frequency range should be 3 - 10 GHz.

thanks for help

Antipodal vivaldis work pretty well at high frequencies, some problems appear at frequencies under 2 GHz. Get in touch with me if you want information on antipodal vivaldi simulation on cst, as i have worked for some time with it

Hope it may be useful

hi,

of course i want help. i don't know how much CST and hfss are similar.

i have build 2 kinds of antennas, an LTSA with an angle of 5.5° , and the vivaldi. but before i build antenna another antenna i want to get used of a simulation tool.

i didn't start with the vivaldi yet because i dont know how to get the exp-funtion. so i tried the linear antenna, but there is also a curve and if i add a curve (half circle) and a line they don't have a polygone after connecting these lines and boolean unite doesn't work either.

maybe you can help me

if u wanna post me: bibijons(at)hotmail.com

tnx

I had added you at my messenger account. If you don't use it, please let me know and I try sending you mails or using this forum. Anyway let me tell you that hfss and cst use completly different ways of solving theelectromagnetic problem though their graphic interfaces and drawing assistants are similar

its me again...

i finished my antipodal ltsa- design on hfss. who can help me with choosing the right port definition ( wave port, lumped port). what do ihave to mention because of my top and bottom layer. my feed is 8mm long and has a width of 1mm. the other side, where i put the ground of a sma, has a widht of 50mm and a lenght of 4 mm.

i put an air box around my antenna, i choosed a high of 15mm in total 30 mm, because of λ/4 at 5GHz is 15mm.
what kind of boundary do i need?

tnx for help

hey all,

I'm still working on vivaldis...

who knows paper that are talking about the circular slot, what is the purpose of it and does any mathmatical calculation exist? the paper i have ( antennas and propatation) are only varify the dimension of it, but there is no formular.

another question is about the Stub. What happens when i increase the angle? how important is the length of it? if you can please send me any formulas too.

most of the times formulas are more helpful, so u can simulate more equations but without the background knowledge its not so useful.

thanks

Buqpa said:

Antipodal vivaldis work pretty well at high frequencies, some problems appear at frequencies under 2 GHz. Get in touch with me if you want information on antipodal vivaldi simulation on cst, as i have worked for some time with it

Hope it may be useful

Click to expand...

can you give me your email add sir?


Minh