Vivaldi Antenna, Simulation and Meaturment results,

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KMPA

Joined: 04 Dec 2003
Posts: 89
Helped: 2

14 Jun 2004 15:29 vivaldi antenna

Hi to all,
I designed a Vivaldi antenna with taper rate of { exp(0.15*z) } in the 500-2500MHz frequency range on RO4003 substrate with Er=3.38 ( Fig.1). The simulation results (Fig.2 and Fig.3) that carried out with Ansoft HFSS V9.1 estimate very good performance (VSWR < 1.6:1 ). but when I construct this antenna and measured input VSWR of it, I saw that VSWR is greater that 3:1 ?? (Fig.4 and Fig.5). I simulate this structure by assuming construction tolorances but simulation results didn't change. I beleave that port definition is wrong.
I upload my structure .sat file, Can anybody simulate this antenna with other softwares (CST or IE3D or ...)

Thanks in advance
KMPA

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gregb3d

Joined: 29 Jun 2004
Posts: 8

29 Jun 2004 22:57 vivaldi antenna cst

Hello,

I'm not sure as to how to help you because I'm just trying to figure out how to draw an exponential taper in hfss v9.1. How did you draw yours?

Thanks

KMPA

Joined: 04 Dec 2003
Posts: 89
Helped: 2

30 Jun 2004 8:07 vivaldi antenna hfss

Hi gregb3d,
I drowe y=f(x) in AutoCAD with a simple AutoLISP code and imported it to HFSS.

eirp

Joined: 11 Dec 2001
Posts: 639
Helped: 9
Location: Phase center

30 Jun 2004 15:01 vivaldi antenna, hfss

Here results calculated by MWS.
The energy has settled down to -40dB.

What port you used in physical realisation? Coaxial to strip transition?

Cheers

eirp

PS: I had to slightly modify the port region by adding small strip feeder. However this won't affect the results a lot.

PPS to gregb3d:

In MWS you can simply create analytical curves using VBA macros accessible from MWS GUI. I don't know if HFSS has also such tool, but it's very practical

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gregb3d

Joined: 29 Jun 2004
Posts: 8

30 Jun 2004 20:31 vivaldi antenna macros

Hi,

I'm simulating your .sat file now in hfss v9.1 and i'll let you know what i get. from my experience it's most likely a port definition problem.

eirp

Joined: 11 Dec 2001
Posts: 639
Helped: 9
Location: Phase center

30 Jun 2004 20:35 vivaldi antenna design

gregb3d wrote:

Hi,

I'm simulating your .sat file now in hfss v9.1 and i'll let you know what i get. from my experience it's most likely a port definition problem.

Hello,

I'm quite sure it's NOT port definition problem.
In MWS the modal solver gives Z0~43Ohm and pure TEM wave as exists in stripline

rgz

eirp

KMPA

Joined: 04 Dec 2003
Posts: 89
Helped: 2

03 Jul 2004 14:54 design an x-band vivaldi antenna part 2

Hi gregb3d,
find, please the attached AutoLisp file,
This file draw a vivaldi curve.

Regards
KMPA

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gregb3d

Joined: 29 Jun 2004
Posts: 8

05 Jul 2004 4:52 vivaldi hfss

Hello,

KMPA:

Below are the results I generated with your .sat file. The s11 results look exactly like yours. I used a waveport in the simulation.

eirp:

You may be right about the port not being the problem but I'm not sure what else could be wrong. Maybe the rad field is too small?

gregb3d

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KMPA

Joined: 04 Dec 2003
Posts: 89
Helped: 2

05 Jul 2004 5:25 design an x-band vivaldi antenna

Hi eirp,
if it possible for you, please post here your simulation project of Vivaldi with MWS,

Thanks
KMPA

gregb3d

Joined: 29 Jun 2004
Posts: 8

05 Jul 2004 14:45 antenna vivaldi ads

kmpa,

Have you tried running your simulation with metal of finite thickness?

gregb3d

KMPA

Joined: 04 Dec 2003
Posts: 89
Helped: 2

08 Jul 2004 13:53 vivaldi antenna formula

Hi,
I used a 35 um thickness for all metals in vivaldi antenna and simulated it again with Ansoft HFSS V9, but VSWR curve didn't change. (jpeg is VSWR)

KMPA

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Alessandra

Joined: 23 Jul 2004
Posts: 9

23 Jul 2004 17:49 antenna vivaldi

Hi!

I have a new trial version of cst, can you send me the file.sat of the vivaldi antenna, so I can try to simulate that?

guanghua

Joined: 19 Mar 2005
Posts: 7

19 Mar 2005 12:21 vivaldi antenna v and h

did you have the hfssv9.1 array model of your vivaldi antenna?i want to simulat it,but i don't know how to formulat the model of vivaldi antenna array?how about your?thanks!

asdfaaa

Joined: 31 Aug 2004
Posts: 237
Helped: 42

23 Mar 2005 2:56 vivaldi antenna

From the *.SAT file:
1. the wave port did not touch both metal plate.
2. the radiation boundary box is not big enough compared with your wavelength.

Simulation is ongoing, I'll keep you updated. At least the part of the result from 0.5~0.8GHz I got is nice, and it is far from your simulation results.

Regards,

guanghua

Joined: 19 Mar 2005
Posts: 7

24 Mar 2005 16:17 vivaldi antenna near field

hi !
I have download your *.sat file and import it in the HFSS v9.0 ,I find that the positon of the top ground plate is not consistent with the sub.maybe that is the reason! I am a beginner of hfss,and i want to simulat vivaldi antenna array ,can you tell me the exictation and the boundary conditions of your example presented
here.From my simulation,the fields plotted on the antenna cannt travel by the way of slot line.can you tell me the reason?The port is wave port and the top and bottom boundary of the antanna is PerE,the right and left boundary is PerH. the wide side of slot line of the antenna is radiation boundary.
thanks

asdfaaa

Joined: 31 Aug 2004
Posts: 237
Helped: 42

25 Mar 2005 5:30 taper for vivaldi antenna

OK, the whole HFSS project file is attached, and part of the simulation results. I dont have enough time to simulate wide frequency bandwidth (even this part of results cost me more than 2 days simulation), but current results at least make sense comparing with the measurement results.

Regards,

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asdfaaa

Joined: 31 Aug 2004
Posts: 237
Helped: 42

25 Mar 2005 5:32 drawing vivaldi antenna in hfss

S11, VSWR, and radiation pattern plot.

Regards,

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asdfaaa

Joined: 31 Aug 2004
Posts: 237
Helped: 42

25 Mar 2005 5:36 cst vivaldi antenna simulation

guanghua wrote:

Yes, the wave port in SAT file is not correctly set up.

About the boundary condition, please check my uploaded project file.

Regards,

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25 Mar 2005 5:36 Ads

guanghua

Joined: 19 Mar 2005
Posts: 7

26 Mar 2005 8:46 vba vivaldi antenna

Thanks a lot !
I have acquired that the wave port in HFSS should be enclosed by PerE boundary conditons,right?The simulation with HFSS needs lots of time. Maybe the simulation of antenna array is out of the question.
Another question about the AutoCAD :How to import the AutoCAD files into the active HFSS window?I have download your example (*.sat)and import it into AutoCAD ,the geometry is shown correct ly in the AutoCAD window.But when I carry out the similar process from AutoCAD file which is obtained by save your example as *.dwg file to HFSS 3D modeler,the error message is "you are importing an native body"! WHY?

guanghua

Joined: 19 Mar 2005
Posts: 7

27 Mar 2005 8:09 vivaldi antenna design equation

Hi !
I want to see the fields distribution on the zone near the vivaldi antenna ,but I can plot the fields on the top and bottom ground plane ,can you help me?The fields dis tribution between the two slot lines can not be viewed?why?

asdfaaa

Joined: 31 Aug 2004
Posts: 237
Helped: 42

29 Mar 2005 13:14 vivaldi hfss parameterize

select substrate surface -> field plot -> mag or Vector of E/H field

Regards,

guanghua

Joined: 19 Mar 2005
Posts: 7

03 Apr 2005 3:52 antenna simulation projects

Thank you!
I can do it !
Another question,How to setup the exitation of the phased array antenna for the beam steer? I know it needs phase shift between elements for the beam scanning,
but how to setup the port in HFSS?I have tried to set different "source setup" of different elements which have the same amplitude but different phase,but the result is wrong!Some articles have presented the methods of "master/slave boundarys" for phased array,how to do it?

snowpea

Joined: 09 Aug 2005
Posts: 1

09 Aug 2005 8:40 received e field of vivaldi antenna

dear guanghua
can we talk about the array simulation of antenna ? my mail is :fanqikai(at)163.com

akedar

Joined: 27 Jul 2004
Posts: 295
Helped: 15

09 Mar 2007 3:49 vivaldi antenna equation

can u help me in designing vivaldi antenna using HFSS
how to model taper...what uis the formula for it...how to model in HFSS
i need to design in X band

freqzt

Joined: 13 Sep 2006
Posts: 123
Helped: 2

09 Mar 2007 9:15 comparing antenna simulation results

I have download the .sat file. I try to simulate it using Micro-Stripes. But I don't know how to make the port and excitation in this simulation. Anyone can help me?

SAJ25

Joined: 13 Mar 2007
Posts: 223
Helped: 20

27 Mar 2007 5:15 4 antenna phased vivaldi array

hi all

if any one have the hfss help or any text about "equation based drwing", i think that it is so usuful for all. please upload it for all.
best regards

akedar

Joined: 27 Jul 2004
Posts: 295
Helped: 15

01 Apr 2007 8:22 hfss 9 trial version

in ur HFSS project why have u defined frequency multiplier = 2 because that we do when we r defining a symmetry plane..that could be a problem

akedar

Joined: 27 Jul 2004
Posts: 295
Helped: 15

16 May 2007 7:27 antenna vivaldi cst download

hey guys

drawing exp curve in HFSS is easy using equation based surface feature

u all can use it instead of going thru AutoCAD tools

if u draw using HFSS u can do optimization of curve to get the results

habeebhabz

Joined: 13 Apr 2007
Posts: 17
Helped: 1

02 Jul 2007 21:42 vivaldi antenna equations

Hello KMPA,

I am trying to design a vivaldi antenna in the frequency range 300 to 800 MHz. I am unable to obtain proper dimensions. Could please upload any material which you have referred, to design yours. I am also getting difficulty in designing proper stipline to slotline transition.

Thanks in advance,
Habeeb.

Added after 1 minutes:

Hi SAJ25,

Its very easy to draw, if you have HFSS v.10

Habeeb.