Vivaldi Antenna Design

EDAboard.com Forum Index -> Electromagnetic Design and Simulation -> Vivaldi Antenna Design

Author

Message

freekman

Joined: 10 May 2007
Posts: 5

31 May 2007 5:37 vivaldi antenna design

Hi... I'm designing a dual-polarized vivaldi antenna which should operate between the frequency range of 2 to 12.6GHz. I'm using the stripline-line vivaldi notch antenna's design. However, i still have many doubts even after reading various journals and articles.

When i'm calculating the wavelength of my stub, cavity and taper, which frequency should i use to determine the wavelength? And how will i know what is my resonance frequency?

And can i use the same concept of the patch antenna to design the microstrip of the vivaldi?

Anyone designing a similar type of antenna? Probably we can discuss more about it.. Btw, i'm using Ansoft HFSS v10 in my design and simulation.

Thanks!

Azulykit

Joined: 18 Feb 2007
Posts: 851
Helped: 103
Location: All over the Map.

31 May 2007 22:13 design vivaldi antenna

I have designed and fabricated Vivaldi's over multi-octave bandwidths. I wonder where you have doubts about them.

When you ask about the stub length I would note that the antenna is operating over a very wide range. Chose a stub length that produces the best match and gain performance. HFSS will allow you to examine this issue in detail. It is a good tool for this application.

A Vivaldi is a slot like antenna while patches are modeled as cavities and thus have very dirrerent philosophies. Patches are not normally thought of as being particularly broadband. Most are well under 20-30 %

freekman

Joined: 10 May 2007
Posts: 5

07 Jun 2007 3:08 wide scan design of vivaldi antennas in s-band

Thank Azulykit..

However, i am still having some problem in achieving a good matching stub. Is there a systematic way in doing this? Any formulas or calculations for the stub design? I dont seem to get a good VSWR and S11 reading. Not sure if i'm doing the simulation properly.

If you dont mind, could i take a look at your design?

Azulykit

Joined: 18 Feb 2007
Posts: 851
Helped: 103
Location: All over the Map.

07 Jun 2007 5:21 vivaldi antenna

The specific details of that design are the property of a former company and I would not want to post them. In reality, I do not have them now for the same reason.

I would start with a stub that is a quarter wavelength (somewhere midband, like the geometric mean) and adjust the length to improve the bandwidth and s11. You might also consider a "pie" shaped stub. There are reports in the literature of people who have had good luck there. The wider stub seems to increase the bandwidth. I have also had reasonable performance with a coax across the slot.

You don't say what you think of as a reasonable match. I can't really comment without knowing your target.

freekman

Joined: 10 May 2007
Posts: 5

10 Jun 2007 1:28 vivaldi antenna

Hi Azulykit,

I'v attached are my design as well as my VSWR and S11 results. I've tried adjusting the stub and cavity size but i still unable to get a good S11 and VSWR reading throughout the bandwidth. My target for S11 is less than -10dB and VSWR of less than 2. Could you please give me some suggestion on how to improve on this? And could you help me check if i have done the simulation correctly? Not sure if there is any problem in my waveport or boundary condition.

Btw, i adjusted my stripline width to match a 50Ω SMA connector which i will connect later on.

Thanks!

Sorry, but you need login in to view this attachment

Azulykit

Joined: 18 Feb 2007
Posts: 851
Helped: 103
Location: All over the Map.

11 Jun 2007 2:02 vivaldi antenna pdf

If it was my problem to evaluate I wold start by modeling the antenna in parts. First I would create the feed line. When that was working I would put a pair back to back and make sure s21 and s11 were both acceptable. Next I would look at the stub and slotline combination and then examine them back to back. If that works I would try a single (planar) vivaldi to see if it was appropriately sized and radiating as expected. Finally I would look at the dual pair.

Locating a problem is easier if one is sure that the design is on firm ground. Make sure the parts are working first and then put them together.

How did these preliminary steps work out in your effort?

bonjelo

Joined: 29 Jan 2006
Posts: 6

10 Feb 2008 16:32 vivaldi notch antenna

Vivaldi model and results presented in attached article

Sorry, but you need login in to view this attachment

snkhan

Joined: 19 Oct 2005
Posts: 294
Helped: 15
Location: Gods place

12 Feb 2008 23:43 dual polarized vivaldi antenna

@freekman
i hope the following paper can help you
Parameter Study and Design of Wide-Band Widescan
Dual-Polarized Tapered Slot Antenna Arrays,IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 48, NO. 6, JUNE 2000

manjushree

Joined: 07 Nov 2007
Posts: 3

13 Feb 2008 12:24 vivaldi antenne design

I woud like to know the measured 3dB beamwidth of the vivaldi antenna.

Regards....

avinashprakhya

Joined: 18 Oct 2007
Posts: 4

14 Feb 2008 6:22 vivaldi antenna dimension

Hi All, I am actually trying to design a very basic CPW fed Vivaldi antenna which can operate in the UWB band of 3.1-10.6 GHz. I haven't started yet but I plan to do this as a part of my Mtech dissertation. I have tried designing with IE3D but ram constratints dont allow me to design in IE3D. Please suggest simulator and also any prior designs would be of great help as i don't find exact dimensions in any of the papers.

snkhan

Joined: 19 Oct 2005
Posts: 294
Helped: 15
Location: Gods place

14 Feb 2008 10:34 vivaldi antennas

@avinashprakhya and manjushree
Vivaldi are basically directional antennas, if u design them on CPW then the pattern becomes ominideational. What else specific details of your design are.

manjushree

Joined: 07 Nov 2007
Posts: 3

15 Feb 2008 12:26 vivaldi antennae

My target of the design of the vivaldi is to realize a very wide beamwidth in the E-plane pattern.
If any of the designers can tell me the 3dB beamwidth they could measure of the vivaldi.

Regards

avinashprakhya

Joined: 18 Oct 2007
Posts: 4

22 Feb 2008 17:28 stripline vivaldi

snkhan wrote:

@avinashprakhya and manjushree
Vivaldi are basically directional antennas, if u design them on CPW then the pattern becomes ominideational. What else specific details of your design are.

In my case of the vivaldi design, I am not quite bothered about the directionality of the antenna. Due to some other problems in my overall project i would have to stick to using a CPW feed.

If anybody has already done a design of vivaldi using CPW(preferrably) or for that matter any other feeding mechanism in 3.1-10.6 Ghz then it would be of great help to me. Please respond !!

Added after 1 minutes:

manjushree wrote:

My target of the design of the vivaldi is to realize a very wide beamwidth in the E-plane pattern.
If any of the designers can tell me the 3dB beamwidth they could measure of the vivaldi.

Regards

@ manjushree : mam do you have any preliminary design of any vivaldi antenna ? if yes then you may upload !!

Google
AdSense
Google Adsense

22 Feb 2008 17:28 Ads

snkhan

Joined: 19 Oct 2005
Posts: 294
Helped: 15
Location: Gods place

23 Feb 2008 8:24 vivaldi notch

@avinashprakhya
Here is a design of vivaldi antenna with CPW. Interestingly the radiation pattern is quite different.

Sorry, but you need login in to view this attachment

avinashprakhya

Joined: 18 Oct 2007
Posts: 4

23 Feb 2008 17:55 vivaldi antenna design procedure

@ snkhan : Hey thanks a lot man for the pdf, but I had that already. What i wanted wasnt a twin structure. I have enough pdfs but nothing mentions the exact dimensions including the one u had jus attached. So i wanted a design in IE3d or cst so that i have a working antenna in place which can then be used for my project.

But thanks once again for the effort.

stayzaroo

Joined: 19 Mar 2008
Posts: 2

20 Mar 2008 0:22 create spline vivaldi antenna

Hello all,
I'm now designing vivaldi antenna with the frequency range of 0.5GHz to 2.5GHz. I got the good S1,1 result in the frequency bands I want. But the main thing I want to know is how to get the constant Beamwidth 90 degree for all the frequency bands. I test the reflector with different kind of angles. But I didn't get the constant beamwidth 90 degree for all frequencies. If you want to see the design I did, then I'm going to upload it.
If anyone can tell me how to get the constant beamwidth in Vivaldi, please give me advices how to do it.
Thank you so much,
S' Tay Zar Oo

Added after 47 minutes:

Here is the VSWR I got in my design.
If anyone can tell me how to reduce beamwidth for 90 degree.
regards,
S' Tay Zar Oo

Added after 1 minutes:

akedar

Joined: 27 Jul 2004
Posts: 295
Helped: 15

23 Mar 2008 12:14 vivaldi notch antenna pattern

VSWR has nothing to do with beamwidth

u have to design and optimise flare for particular beamnwidth desired..normally beamwidth decreases with frequency..so design optimally..see some paper in IEEE they have lots of info on this

or leture note o notch antennas by simons

stayzaroo

Joined: 19 Mar 2008
Posts: 2

24 Mar 2008 0:42 tapered slot antenna coaxial

Hello Akeda,
Thank you so much for your helps,
I use reflector in Vivaldi antenna. I want the beamwidth 90 degree in that 3 frequencies ,0.9GHz, 1.8GHz and 2.1GHz almost 90 degree beamwidth. I tested with circle reflectors but the difference of beamwidth is almost 50 degrees in 0.9GHz and 2.1GHz. I want the beamwidth difference about 20 degrees in 0.9 and 2.1. Would you please give me some idea for that?
Would you please tell me how to get the lecture not on patch antenna by simons?
I want to learn from that.
If you don't mind, would you please help me how to get that lecture notes?
Thank you so much for your helps,
stayzaroo

Sorry, but you need login in to view this attachment