eco32

Design with slot or with  coaxial splited balun - the reflector disc is smaller than the previous design, I guess that's the reason for the lower gain.

On 27.05.2023 at 9:33 AM, Admin said:

,,,yes, it seems that this dipole with circular reflector is good....!!!

WOW! The antenna is very broadband! It Covers the entire 23cm band, this type of design is also suitable for LTE/5G

I have read that for grid parabolic antennas the reflector can be narrower, it does not have to be a circle, it can be a rectangle with rounded corners

With  my firs 13dBi design, I made the QSO with 250mW over a distance of 8km using the reflection of a tall office building. (I have different grids: 600mmx400mm 13dBi, 700mm x 900mm 17dBi)

On 24.05.2023 at 8:14 PM, Admin said:

,,,old trash...!!!

MIT Radiation Lab Series V12 Microwave Antenna Theory and Design  1949 

chapter 8 Microwave dipole antennas and feeds

https://www.scribd.com/document/35903457...and-Design#

This type of antenna is patented : US5191350 LOW WIND LOAD PARABOLIC ANTENNA, for more details check pdf file.

US5191350 LOW WIND LOAD PARABOLIC ANTENNA.pdf

Thats grid with dipole rear feed with splited coaxial balun, basic version (1) with one reflector on the feed

Diameters for a 1296MHz

On 15.05.2023 at 0:34 PM, Admin said:

,,,yes, it fits...!!!!

 

     Hi, it looks very good!

Could You try diameters for a 1296MHz?

lambda      127.118644      lamda      231.481481

13cm(inch)      13cm(inch)      13cm(mm)      alfa      23cm

2+1/2      2.5      63.5      0.49953333      115.632716

11/64      0.171875      4.365625      0.03434292      7.94974923

1+1/4      1.25      31.75      0.24976667      57.816358

1+27/64      1.421875      36.115625      0.28410958      65.7661073

1+3/32      1.09375      27.78125      0.21854583      50.5893133

2+7/16      2.4375      61.9125      0.487045      112.741898

 3/16      0.1875      4.7625      0.037465      8.6724537

 15/16      0.9375      23.8125      0.187325      43.3622685

2+7/16      02-Jan      61.9125      0.487045      112.741898

something about thos antenna from 1968

The Radio Amateur's V.H.F. Manual  - A Manual of Amateur Radio Communication on the Frequencies Above 50 Megacycles  1968

https://dokumen.pub/the-radio-amateurs-vhf-manual-a-manual-of-amateur-radio-communication-on-the-frequencies-above-50-megacycles-11th-ed.html

(I will try do my own for a 1296MHz)

From the description, it seems that it is not a "simple dipole" but a slot antenna.

It is based on Pacyfic Grid 917x720 and 15cm deep 5.6GHz grid antenna symulation + Yagi Uda in revers - directors works likea rediators (This is not a good representation, Matlab has big limitations)

1296MHZ => 17.3dBi

oryginal grid antenna https://www.cyberbajt.pl/produkt/350/pacific-grid-56-ghz28-dbi.html

I cannot find a commercial implementation of such an "feed"  also no publication with  "rear dipole feed with two reflectors". May the name is very specific, google does not return anything meaningful.

Thank You!, please give me few days to build this, i will show You the result

i like to try do  such feed for a 1296MHZ, but I'm not sure about the dimensions, colleagues please tell me what would be the dimensions for a model with two reflectors. This one is too short, I modeled in matlab, resonance at 1500MHz (split coaxial balun):

That's my version of this antenna:

(BOX completely incidental, should be other size)

size

55x38x26cm

bottom : 51x34cm

On 13.05.2022 at 10:38 PM, Dr. Pepper said:

Biquat + Horn for 2.4 - 2.5 GHz & optimized for gain

 

 

 

 

WOW!

@Dr. Pepper You got 16dBi !!!  I got only  14dBi

I cant change angle of the box in Matlab, thats my limitation.

I like to try it on 1296MHZ

@AdminMay We have other section for 1296MHZ 23cm band antennas?

8 hours ago, Admin said:

,,, these would be the simulations and dimensions...!!!!

Thank YOU!

I see the qain is smaller than I got, how it will be with 90deg, i belive that is possible to get 14dBi

"What else, what profit can it give."

@Harry36 :

I am curious with a bi-loop "in the box" I will be able to get more gain than a biquad, smaller in size, or a better shaped beam

I don't have the tool to check this, Matlab antenna toolbox has some limitation.

box diameters: 40cmx27cmx20cm +/- 1cm

On 16.01.2017 at 4:36 PM, Admin said:

,,,a biquad antenna on PCB(10,5dBi) and panel antenna with 4biquad(16.5dBi)...

.....

Hi @Admin

Could You Please symulate it for a 1296MHZ (23cm ham radio band)?

I will try to cut this shape in laser from metal sheet. Thats my idea to add N or SMA  connector. Lets fin out, how it will work with comparing to my biquads

 in the simulation I achieved 14dBi. This brim is shallower than the simulation assumes, it could be 11.3 dBi. The antenna is very effective. I'm thinking of replacing the quadrates with loops. I'm thinking of a similar implementation as in the attached pictures, not laminate.

@Harry36 Thank you for the clarification.

With this antenna I am receiving ham radio beacon beacon SR6 LHZ 1296.830 with level -80dBm - distance 111 km, power 1W

My aim is to increase the gain of a single biquad. maybe changing the shape or geometry will help.

That is my antenna:

I am thinking of using bi-loop instead of biquad, I use matlab on a daily basis, and I have not yet managed to make a model, I am currently unable to check

1) Bi-Loop is mechanically simpler to make, tune and correction.

What else, what profit can it give.

In publication about this antenna for a 2,45GHz:

"The simulation results showed that the best parameters value are 14.95 mm of loops radius, 1.15 mm of links radius, and 15.57 mm of reflector gap. In these parameters, the antenna had a characteristic value of return loss -36.65 dB, bandwidth 354 MHz"

IMG_1496.webp