Lutenna - The antenna made of Sugar

**casser** · 14-03-2009

It´s not my invention, but i should be the first to build a multibeam antenna made of sugar

I´m preparing a PDF to explain the antenna and some possible versions of these type of antenna.

**casser** · 16-03-2009

humm..nobody comment, maybe nobody believe in a antenna made of sugar?

I didint had time to translate my PDF about these antennas, so i will give a little explanation.

The idea came from Farragsat antennas, then i study a little a couple of articles on the internet..what i understand:

Luneberg invented this type of antennas in the 40´s, but he proposed that the antenna should have several layers of dielectric materials. The highest dielectric material should be at the surface of the antenna and the lowest should be inside of the antenna.

But building a antenna according to Luneberg theory it´s very hard because the need of several layer´s of materials. So i tried a one layer version..having a dielectric constant of 2.0 (Sugar in this case).

In a single layer version, the dielectric constant is what determines the focal point of the antenna, lower is the dielectric constant of the material..far is the focal point. But if the dielectric constant is 2.5, the antenna will not work, because the Focal point will be "inside" the antenna. A good around dielectric constant to medium size antennas should be between 1.6 and 2.2.

There are a lot of materials that can be used..sugar is one, dielectric foams should be perfect

There are a lot of versions:

-A full Sphere
-Half-Sphere
-Half-Shpere cutted (to reduce the volume of the antenna)
-Half-Sphere+conical Horn
-Half-Sphere+dielectric conical horn
-Half-Sphere+reflector
...

Make your own homemade multibeam high efficiency antenna using cooking materials

**pipino** · 16-03-2009

hi.
thanx for sharing with us this strange looking antenna,but since its sugar with water would melt and with sun will cock to caramel state,could you use other material like concrete or sand??

**Topper** · 16-03-2009

Not really sure where this is heading, since I was under the impression that all dishes (with exception of a torroidal) were simply sections cut from part of a sphere. If they were not cut from part of a sphere they would not have a focal point, the focal point of which is determined by the original diameter of the sphere they were cut from.

Apart from the sugar what is new here?

**casser** · 16-03-2009

Originally Posted by pipino

hi.
thanx for sharing with us this strange looking antenna,but since its sugar with water would melt and with sun will cock to caramel state,could you use other material like concrete or sand??

Sugar is the only material that i know thar work..but it´s probably the worse material, 2 days in the outside, the sugar will crystallize.

The material like i said before, should have a dielectric constant between 1.6 and 2.2 and it should not be very lossy at 11.75Ghz.

Check this sites, and search for better materials:

_http://www.clippercontrols.com/info/dielectric_constants.html
_http://www.deltacnt.com/99-00032.htm
_http://www.rafoeg.de/20,Dokumentenarchiv/20,Daten/dielectric_chart.pdf

Originally Posted by Topper

Not really sure where this is heading, since I was under the impression that all dishes (with exception of a torroidal) were simply sections cut from part of a sphere. If they were not cut from part of a sphere they would not have a focal point, the focal point of which is determined by the original diameter of the sphere they were cut from.

Apart from the sugar what is new here?

This is not a dish..this is a dielectric spherical antenna, only the version with reflector have metal, all others doesnt have a bit of metal on it.

The shape of the Sphere is what makes the signal focal to a point, but the distance of the FC to the antenna is determined by the dielectric constant of the material, not by the size of the sphere..example for a Sphere (not real values):

Sugar have DC=2.0

-In a 20cm diameter version, the focal point is at 30mm of the antenna
-In a 40cm diameter version, the focal point is at 30mm of the antenna.

Cadmium oxide, DC=1.6

-In a 20cm diameter version, the focal point is at 100mm of the antenna
...

Trust1 · 16-03-2009

The same princyple ?

***CROSSBONES*** · 16-03-2009

I read an article in Telesatellite, about an Indian guy who did the same set up on a globe type dish

**Analoguesat** · 17-03-2009

Fascinating casser

As a matter of interest how well does it perform?

**casser** · 17-03-2009

Originally Posted by Trust1

The same princyple ?

Yes, there are some (few) companies trying to put these antennas on the market..

See this video for a motorized version to work on a train, another thing about these antennas is using a motor, the antenna doesnt need to move, only the LNB

:

_http://www.technologyreview.com/video/?vid=199

Originally Posted by CROSSBONES

I read an article in Telesatellite, about an Indian guy who did the same set up on a globe type dish

All my ideas came from that Indian guy (Farragsat), but i dont know how did he get some very high efficiency antennas

I can get 130% in a 15cm version, but bigger the sizes, smaller is the efficiency..but i dont believe anyone using a 1.5meter sphere..the dimensions/volume are....

A 62cm half-version without reflector (10cm cut to reduce volume)..have 36.2dBi, +-70%.

Originally Posted by Analoguesat

Fascinating casser http://www.satellites.co.uk/satellit...lies/smile.gif

As a matter of interest how well does it perform?

I believe the antennas have the same 3dB extra gain like Conical Horn´s..adding the high efficiency (100%), a 40cm version will perform like a 80cm dish. Adding to their multibeam capabilities, i think is the perfect antenna for medium dimensions. I have a feeling that a half version with reflector loose the 3dB extra..

Check farragsat site, he says that a 50cm version (with 35dBi) can receive up to 45dBW satellite..

The secret of these antennas is the material to use on it and since one layer version works pretty good..it´s much more simple than the original Luneberg principle. All we need to get is a right material with a DC between 1.6 and 2.2 and it should not be very lossy at 12.75Ghz. This sugar version is a life dream for ants

I prefer to look for Powdered/small granulated materials because the density of materials change the dielectric constant. It can be a material so simple like Sugar (i was lucky on this one), but it can be a bunch of other things..Maybe it´s possible to get a powdered material with DC >2.2 and mix with styrofoam (DC=1.02, which is pretty close to vacuum), and get the perfect DC.

A 25cm version will work up to 50dBW, if you want to try some powdered/granulated materials, get a "street ball of lightning" / beach ball / basket ball/ anything oval (except glass/metal balls)..make a hole in it, and fill the ball with the material. If the material have a DC=2.0/2.1, the FC will be almost at the surface of the ball, lower is the DC.. far is the FC from the ball.

Sorry for the long statements..but more people understanding how simple this antenna is, more people will try it using different materials, more easily we can get the perfect material to make our own multibeam/multifrequency/high efficiency antenna

**Low Profile** · 17-03-2009

If you can get the outer DC to around 1.7 then this will give you an effective F/d to around 0.6 - ideal for generic LNBs!

**Low Profile** · 17-03-2009

Are you sure you can get Styrofoam (Expanded PolyStyrene) with a DC as low as 1.02? I thought that normally it's around 2.5

**Low Profile** · 17-03-2009

From what I've seen, LL's have a gain similar to dishes of the same size, not sure about noise levels, but I think that effective beamwidth may come into play. A hemi should have roughly the same gain as a full sphere.

**casser** · 17-03-2009

Originally Posted by Low Profile

Are you sure you can get Styrofoam (Expanded PolyStyrene) with a DC as low as 1.02? I thought that normally it's around 2.5

Polystyrene have 2.5-2.6, but the expanded polystyrene have 1.02-1.08, put a brick of styrofoam in front of a dish it wont affect the signal..it´s almost vacuum.

I will get a bag of styrofoam (loose form) and try some mixes with sugar to see if the Focal Point is affected, if have the same signal and the FC get´s longer...so using styrofoam with materials lower the dielectric constant of the antenna.

Do you know what´s the impact of the "Loss Tangent" in these types of antennas? It can affect the performance of the antenna using a high "Loss Tangent" material?

**Low Profile** · 17-03-2009

Originally Posted by casser

Polystyrene have 2.5-2.6, but the expanded polystyrene have 1.02-1.08, put a brick of styrofoam in front of a dish it wont affect the signal..it´s almost vacuum.

I will get a bag of styrofoam (loose form) and try some mixes with sugar to see if the Focal Point is affected, if have the same signal and the FC get´s longer...so using styrofoam with materials lower the dielectric constant of the antenna.

Do you know what´s the impact of the "Loss Tangent" in these types of antennas? It can affect the performance of the antenna using a high "Loss Tangent" material?

The higher the loss tangent, the less signal will get through the lens, so you want it to be as low as possible.
I had considered making a (large) transparent lens.......
Until I considered the solar effect

**casser** · 17-03-2009

Originally Posted by Low Profile

The higher the loss tangent, the less signal will get through the lens, so you want it to be as low as possible.
I had considered making a (large) transparent lens.......
Until I considered the solar effect

Transperent lens should be stylish, but..

Thanks for the "Loss Tangent" info, unfortunately is rare to get information about the Loss Tangent of each materials..only RF Cafe have some information:

_http://www.rfcafe.com/references/electrical/dielectric-constants-strengths.htm

Another material that possible work is wood shavings, i filled the 12cm version with shavings, got 17% of signal..with sugar i have 45%, so i dont know if i filled the ball with few or too many shavings to get the poor result´s, or maybe it´s the Loss Tangent of wood.

Pressed board made of wood have a DC between 1.6 and 2.6, but no Loss tangent info.

Cat´s litter is another material i will try someday

The ideal material should be Teflon, but it would become the most expensive homemade antenna ever made..

Just for curiosity.. LUTENNA = Luneberg + Antenna

**casser** · 17-03-2009

Rudimentary 2D images of the many versions that could work..

**casser** · 31-03-2009

Just got confirmation that granulated Polystyrene works

A portuguese user from another forum, said that polystyrene have the same performance like sugar..but the LNB should be placed 2cm away from the position using sugar. This suggest´s that the dielectric constant of granulated polystyrene is 0.1/0.2 lower than sugar.

I dont know if there are different types of granulated polystyrene, but it´s better than having sugar in the outside.

krithika · 01-04-2009

Thanks for opening such a nice thread. I have few doubts. Can we use these following materials instead of sugar? Charcoal 1.2-1.81, Cement 1.5 - 2.1, Cement, Portland 2.5-2.6, Ash (Fly ) 1.7 - 2.0?

Suppose I buy a big plastic/rubber ball and fill it with one of these above materials can I get signal? Is it as simple like that or I miss some thing else?

**casser** · 01-04-2009

Originally Posted by krithika

Thanks for opening such a nice thread. I have few doubts. Can we use these following materials instead of sugar? Charcoal 1.2-1.81, Cement 1.5 - 2.1, Cement, Portland 2.5-2.6, Ash (Fly ) 1.7 - 2.0?

Suppose I buy a big plastic/rubber ball and fill it with one of these above materials can I get signal? Is it as simple like that or I miss some thing else?

All you need is to fill a ball with the correct material, or if it´s possible, make a sphere with that material...nothing more is needed.

But i recommend to try a smaller version (ex 15/20cm) just to understand the antenna, before starting in bigger versions. I never confirmed bigger full spheres versions than 25cm to work like predicted, it can be a bad surprise.

I believe that a 25cm version can receive up to 50dBW satellite.

About the materials, there are only confirmed two materials to work (with same performance)
-Sugar
-Granulated Polystyrene

Both have pretty much the same weight. About other materials, i cannot say for sure if it works or not...because no one try it so far. Another portuguese user tried Powdered Charcoal (he smashed the charcoal), but didint work. But it´s so simple to test a granulated/powdered material..all you need is to fill a ball

**Low Profile** · 02-04-2009

The loss will be too high in those materials IMO.

**casser** · 02-04-2009

Originally Posted by Low Profile

The loss will be too high in those materials IMO.

In what materials your´re saying?

But i´m a bit affraid if the materials are very lossy, bigger spheres will have less efficiency, since the signal needs to pass throught a lot more material than in smaller versions..i dont know if this can happen..

**Low Profile** · 02-04-2009

Originally Posted by casser

In what materials your´re saying?

Charcoal 1.2-1.81, Cement 1.5 - 2.1, Cement, Portland 2.5-2.6, Ash (Fly ) 1.7 - 2.0

I can reckon those materials will be very lossy (but admit that I haven't looked up their loss coeffs).

You may find that loss coeff changes with frequency (or maybe that should be with wavelength).

Going back to the lens suggestions, the BIG advantage of a true LL is that it doesn't need to be moved to catch different sats (the LNBs just need to be placed correctly). If you want to adapt the lens as you suggested then you will find that you can only efficiently receive one sat at a time, and you would have to move the lens to focus on any other sat.

**casser** · 03-04-2009

Originally Posted by Low Profile

Charcoal 1.2-1.81, Cement 1.5 - 2.1, Cement, Portland 2.5-2.6, Ash (Fly ) 1.7 - 2.0

I can reckon those materials will be very lossy (but admit that I haven't looked up their loss coeffs).

You may find that loss coeff changes with frequency (or maybe that should be with wavelength).

Going back to the lens suggestions, the BIG advantage of a true LL is that it doesn't need to be moved to catch different sats (the LNBs just need to be placed correctly). If you want to adapt the lens as you suggested then you will find that you can only efficiently receive one sat at a time, and you would have to move the lens to focus on any other sat.

I also think those material´s are very lossy, but is rare to get loss tangent values for each material, so the best way to confirm is to test the material.

There are tons of articles about sphere antennas, this one is about adding a second smaller sphere in the focal point of the biggest sphere:
_http://www.waset.org/pwaset/v37/v37-118.pdf

The Half-lens or Half-lens+conical is made for one sat only, maybe can receive different sat´s better than normal dish...but the multibeam capabilities is lost when the sphere is cutted in half.

Since i posted this antenna in a portuguese satellite forum, many people tried the antenna with different material´s, some homemade support´s for the LNB are very curious..

i´ll try to upload some photos of the antennas that they made.

krithika · 07-04-2009

Still waiting for the photos

**casser** · 08-05-2009

Originally Posted by krithika

Still waiting for the photos

Sorry for only replying now...but i´m in vacation

I´ll ask the author´s of the photos if i can upload their photos here in satellites.co.uk.

BUT..there is a major problem with using one material only, a 40cm version is working almost the same that a 25cm version (full lens or half-lens)

(tested with sugar and granulated polyestirene)

In theory (from simulations at university) it should work with only one material, but maybe the loss tangent is messing a lot more than i expected.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Lutenna - The antenna made of Sugar Upload your photos here (Don't link to them with img code, upload them), doesn't matter how basic your setup, it's nice to see what everyone is working with. If you've seen an interesting setup, then post it here. All photos here are copyright and cannot be used without permission of the poster.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)