3 ms·

Nice work! I look forward to following your development. As a radio amateur I was looking at a Luneburg lens for a 10GHz point to point link, with luck this wil

Nice work! I look forward to following your development. As a radio amateur I was looking at a Luneburg lens for a 10GHz point to point link, with luck this will let me play around with that idea. Is there a discord server or forum where folks are discussing applications?

jboirazian 2y ago
Hi ChuckMcM! If you are interested , i also developed last year a PLA Luneburg lens for Band X (8Ghz to 12Ghz) using a conventional FDM printer. We obtained a 6dbm gain @10Ghz https://github.com/jboirazian/LuneburgLensGenerator https://github.com/jboirazian/LuneburgLensGenerator https://polar.sh/jboirazian/posts/why-luneburg-lenses-are-cool-as-f-ck https://polar.sh/jboirazian/posts/why-luneburg-lenses-are-co...
- ChuckMcM 2y ago
  Awesome. That is pretty much exactly what I was thinking of doing. My thought was that you could more easily weatherize something like this rather than a parabolic dish which has a lot of wind loading. What filament did you use?
  - jboirazian 2y ago
    Conventional PLA. Since its the cheapest and surprisingly extremley stable for Ghz range RF applications I recommed you to read the research paper "Measuring the Electrical Properties of 3D Printed Plastics in the W-Band " (https://scholarworks.uark.edu/cgi/viewcontent.cgi?article=1086&context=eleguht https://scholarworks.uark.edu/cgi/viewcontent.cgi?article=10...) It was really useful for us when developing our lens with an FDM printer. Be warn that it does require an infill of 100% , so it will be quite heavy.
- GeorgeTirebiter 2y ago
  6 dB gain? 'dBm' is db gain relative to 1 milliwatt of power.
  - ChuckMcM 2y ago
    Based on the literature the measure would be 6dBi (relative to isotropic). This is often referred to as 'gain' as it represents sensitivity to the band of interest at a given angle of arrival.
    - GeorgeTirebiter 2y ago
      Yes, antennas are normally measured relative to the theoretical 'isotropic' radiation pattern. Sometimes, dBd is used - gain relative to a dipole. But, even then, you have pattern E and H plane measurements. https://www.data-alliance.net/blog/antenna-radiation-patterns-hplane-eplane-xy-xz-yz-planes/ https://www.data-alliance.net/blog/antenna-radiation-pattern... We'll discuss this with an eyeball QSO in November...
      - ChuckMcM 2y ago
        In the paper they were measuring signal gain between two antennas, and as such the 6dBm gain appears to be the effect of collating more of the beam spread into the receiver (as one would expect of a lens). Given my schedule I don't think I'll have enough time to print one by November but it would make for some excellent discussion! Reading the permittivity paper that was linked here was also quite good and I'm wondering if something could be integrated into openEMS which would tie the two together. I'm also tickled by the idea of a 'Newtonian' RF telescope using two lenses.

jboirazian 2y ago

Hi ChuckMcM! If you are interested , i also developed last year a PLA Luneburg lens for Band X (8Ghz to 12Ghz) using a conventional FDM printer. We obtained a 6dbm gain @10Ghz https://github.com/jboirazian/LuneburgLensGenerator https://github.com/jboirazian/LuneburgLensGenerator https://polar.sh/jboirazian/posts/why-luneburg-lenses-are-cool-as-f-ck https://polar.sh/jboirazian/posts/why-luneburg-lenses-are-co...

ChuckMcM 2y ago
Awesome. That is pretty much exactly what I was thinking of doing. My thought was that you could more easily weatherize something like this rather than a parabolic dish which has a lot of wind loading. What filament did you use?
- jboirazian 2y ago
  Conventional PLA. Since its the cheapest and surprisingly extremley stable for Ghz range RF applications I recommed you to read the research paper "Measuring the Electrical Properties of 3D Printed Plastics in the W-Band " (https://scholarworks.uark.edu/cgi/viewcontent.cgi?article=1086&context=eleguht https://scholarworks.uark.edu/cgi/viewcontent.cgi?article=10...) It was really useful for us when developing our lens with an FDM printer. Be warn that it does require an infill of 100% , so it will be quite heavy.
GeorgeTirebiter 2y ago
6 dB gain? 'dBm' is db gain relative to 1 milliwatt of power.
- ChuckMcM 2y ago
  Based on the literature the measure would be 6dBi (relative to isotropic). This is often referred to as 'gain' as it represents sensitivity to the band of interest at a given angle of arrival.
  - GeorgeTirebiter 2y ago
    Yes, antennas are normally measured relative to the theoretical 'isotropic' radiation pattern. Sometimes, dBd is used - gain relative to a dipole. But, even then, you have pattern E and H plane measurements. https://www.data-alliance.net/blog/antenna-radiation-patterns-hplane-eplane-xy-xz-yz-planes/ https://www.data-alliance.net/blog/antenna-radiation-pattern... We'll discuss this with an eyeball QSO in November...
    - ChuckMcM 2y ago
      In the paper they were measuring signal gain between two antennas, and as such the 6dBm gain appears to be the effect of collating more of the beam spread into the receiver (as one would expect of a lens). Given my schedule I don't think I'll have enough time to print one by November but it would make for some excellent discussion! Reading the permittivity paper that was linked here was also quite good and I'm wondering if something could be integrated into openEMS which would tie the two together. I'm also tickled by the idea of a 'Newtonian' RF telescope using two lenses.