HELP: What is the name of this antenna ?

Hi,

Could someone tell me what is the name of this antenna ?
Array of bended Dipole ?

THanks
oxo

Something is missing from your diagram. Is there a ground plane and another plane of patches?

flatulent:
Yes, on the back, there's a similar patch, which is connected to ground.

You know the exact name of this?

This looks like an array of linear dipoles with some tapering of the feed power. Notice the different line widths at the outer corners. This is probably due to the need to reduce sidelobes. There is no special name for this as an array of linear dipoles was the first type of gain antenna invented.

Yes, you are right: an array of simple dipoles. I didn't see it !

Now,
a) How would I change this to a dual-polarized array ?

Is it as simple as rotate half of the number of dipoles 90 degree so half of them will be vertical, the other half is horizontal ?

b) If I make the substrate very extremely thin, are the widths of the traces wider or narrower ?

c) If I make the substrate very extremely thin, what will change (gain, beam-width, bandwidth?)

Thank you for you time,
oxo

1. To get CP you have to do a combination of rotating the dipoles and increasing the transmission line length by 90 degrees. If you do not do the 90 degree thing you will only get linear polarization at a 45 degree angle.

Depending on which ones get rotated, you will get CP directly on axis but off axis it will be elliptical. The only way to get CP over a wide beam angle is to have the dipoles at right angles share the same center point. This makes the feed more difficult to do with just two metal layers.

2. When the substrate becomes thinner you have to narrow the transmission line trace widths to maintain the line impedance. This will increase the transmission line attenuation. With such short lines this will probably not be any significance.

Flatulent:

Thank you for yr help so far.

I think this array is broad-side radiation.

Using the same array, do you know what will determine if it's Broad-side or End-fire radiation ?

Do you think to make it end-fire, I just have to remove all dipoles, except the top row ?

Thanks alot,
xox

The direction of the radiation is set by the relative phasing of the dipoles. In your case the line length to each one from thee main input are equal. This will radiate broadside.

My friend Flatulent,

I'm having so much problem to obtain a single main beam from this dipole array (See picture).

Simulation 1: 2 main beams.

So I reduced the distance between the elements to less than lamda/2.
Simulation 2: still 2 main beams (See picture).

What can I do to avoid double beam? I"ve reduced the inter-elements distance the maximum I could.


Thanks alot.
xox.

Very bad picture but it looks like 4 stacked dipoles.

its a two element yagi with reflector

your feed point is in the wrong place

it shouldnt be in the middle of the array

it should be at one end or the other

i think the reason for the two beams instead of one beam

is the way you are feeding the array .

try to feed the lower line to the upper line instead of feeding it to the ground .

(do it with a discrete port ).

and then each line will be with a opposite phase (0,180).

I'm doing exactly the same thing:
>>try to feed the lower line to the upper line instead of feeding it to the ground .
>>(do it with a discrete port ).

The lines are supposed to be correctly spaced and phased. But what should I do for this ?:
>>and then each line will be with a opposite phase (0,180).

Thanks

The figure is not clear, but the beam is a difference beam, you have some electrical or mechanical out of phase of 180° among the array elements.

Hi costox

Look at this it explain all
I think that you switch the lines in the second power divider.
pl

Thanks plasma.

You are right. I used symmetry plane but after looking carefully, my symmetry plane was wrong.

Now, if you don't mind, I also wonder why the feed-line going to EACH PAIR of dipoles has different width (different impedance). Closer to edge: narrow. Closer to center: Wider.

Thank you all.
xox

Hi costox

Do you have CST file or just a picture?

if it CST file just pm the file and I'll try to help you with it.

you can pm the mod and par files. or go to MACRO -> FILE -> ARCHIVE you will get zip file.

pl

Hi,

Is it possible to get the paper / source of the the design? It could be useful for me.

Thanks.

That is a Dielectric Resonator Antenna Array,
the radiating elements are not what it looks like a "dipole"
but the block on the other side of the ground plane
feeded by a slot on it, see Fig:1.30:

Hi friend Jallem,

Do you know the name of the book of that DRA array photo 1.31?

Thank you friends.

xox