Helix Antenna

[Admin 2545]

A method to improve the gain of axial-mode helical antenna is proposed.

This method involves a parasitical circular metal disk,which is installed on the front of general axial-mode helical antenna and is apart from the helical line. A circular current whose phase lags behind that of helical line current appears,which brings a more concentrated radiation field. Consequently,the antenna gain is improved, Based on the simulation results,an antenna array model fed independently is proposed.This model gives an excellent explanation of the radiation characteristic of helical antenna, Both the simulation and experiment results show that for obtaining the same gain,the antenna length in this new method is only 71% of that in traditional helical antenna.The reduction of antenna length favors the miniaturisation of antenna.

In addition, this method has a little effect on the bandwidth of antenna, so it can be widely used in the design of helical antenna element and array.

 

[Admin 2545]

This type of helical antennas with a parasitic element directory is used for remote control of drones

 

 

 

[Andrew77 6]

Can this disk be applied to longer helical antennas (2 wavelength) and @ lower frequency? (EG 430 MHz)??

thanks

 

[Admin 2545]

2 hours ago, Andrew77 said:

Can this disk be applied to longer helical antennas (2 wavelength) and @ lower frequency? (EG 430 MHz)??

thanks

 

Yes, this parasitic disc can be applied but only at helical antenna  with 3...5 coils or at least reduced by 70-71%.!

[Admin 2545]

Satellite Helix with Patches

[Andrew77 6]

impressive!

 

[antenna_kid 13]

Hi, 
has you any design files how to make such antenna ?
I would like to try my skills

 

[Admin 2545]

9 hours ago, antenna_kid said:

Hi, 
has you any design files how to make such antenna ?
I would like to try my skills

 

which antenna?

[antenna_kid 13]

On 4.10.2016 at 1:30 PM, Admin said:

 

 

 

interested in such antenna. Made helicals for 5.8Ghz and 2.4 ghz. they are good but long. Helix with parastic element is what i've looked for.
This helicals are so short, that i would like to try make a 2x2 array.

[Admin 2545]

Ant_kid, are you interested in antennas for drones?

[antenna_kid 13]

Hi, yup. I'm DIY fan. Love drones, but making things gives me more fun. I've made small CNC, 3D printer. Just love DIY.

[Admin 2545]

,,,and a helix much simpler...

[grocket 2]

I am new to this forum.  Impressive work here.

I love it.  I would love to try this one..where could I get the dimensions/original research?  That coil spacing/angle is impressive.  

I have used the parasitic disk concept successfully as seen in the pics.  3d printed construction for accuracy.  Inset wire grove and parasitic standoff.  They are much more compact.  I use them on my 2.4 ghz RC transmitter with cp biquad on the receiving end. Massively improved range, but more importantly no dropouts or fly-aways.

[Admin 2545]

,,,hi buddy...!!!

"impressive, did you make these helix antennas ...?

[grocket 2]

Yes, went through a few iterations on the 3d print/construction. Just dialed (range tested on ground and in air) them in last week.  11.3 deg on the coil. In practice the disk really seems to punch the signal through...no drop outs.

 

[Admin 2545]

ok, from where did you get this helix geometry...??

 

 

 

[grocket 2]

That is the research I used to construct them.  Used fusion 360 design and print in ABS.  Unfortunately, it does not address  design parameters...just concepts.  I would like to apply it to other frequencies, but it would be impossible to experimentally determine parasitic disk size/distance.  I do not have test equipment or simulation software.

Is there any free online simulation software available similar to what you used above?   Looks expensive.  Thank you for the help.

[Admin 2545]

You can try this....https://www.sonnetsoftware.com/products/lite/download.html

[grocket 2]

Thank you. I will have to get this on my older PC, as I currently use a Mac.

I would like to try a 1x2 array with the 3 turn I am using shown above.  What distance would I use?  or what equation will determine the minimum distance between coils (multiples of wavelength)? Reflectors to edge sounds too easy.

I also applied this to a 3 turn at 5.8 ghz.  

 

[Admin 2545]

...the minimum distance between coils = 0,62*lambda ( wavelength )

....the bestt distance between coils = 0,8-0,9*lambda ( wavelength )

[grocket 2]

Fantastic..I will give it a go.  Thank you so much for actually replying and fast!

In your above example using tape rather than wire...I would like to use tape rather than wire, what design adjustment will I need to make.  For example I used 2mm wire on the 2.4...6mm tape ok?

[grocket 2]

BTW, the distance between coils..from the outer edge of the coils, right?  Not the centers..

[Admin 2545]

,,,from center to center coils...

0,025*lambda = tape

 

[grocket 2]

Thank you!

[grocket 2]

I have been working on feeding my helical from the center of the coil and using a rectangle impedance matching stub.  I am not sure how to account for the length leading to the center feed (1/2 radius of coil).  

Example: 3 turn helical + coil radius feed= Frequency change?

Also, do I use the same impedance matching stub size when feeding from the center?  I hope I explained myself correctly.  Thank you.