Biquad Antenna

[Dr. Pepper 58]

This is indeed much simpler and more stable over a wide frequency range. The idea with the directors is also not bad, perhaps with this the reflector can be a little bit smaller.

[Dr. Pepper 58]

Updated version of the Biquad in a pot for 2.4 GHz, this time with a better impedance match over a wider frequency range and vswr starting at 1 ;-). But as mentioned before there are better designs out there.

Parameters

Quote

wsq="5.7" "with square"
lsq="26.6" "length square"
h="30.7" "height"
g="0.5" "thickness mat"
w="(l-wsq)/2" "with biquad"
ded="l/4-we1/2" "distance edge"
ded2="l/4+we1/2" "distance edge 2"
l="136.1" "length biquad"
e="5.3" "edge 3 biquad"
s="7.3" "hole diameter"
s1="43.4" "length slot"
sl="0.3" "slot"
x="248.2" "reflector x"
y="128.7" "reflector y"
we1="5.3" "with edge 1"
hc="177.0" "height collector"
ang="13.9" "angle collector"

 

[Harry36 140]

You don't have sidelobes on the x-axis and quite large on the y-axis. Try resizing the reflector ;-) , this should help flatten the radiation pattern and raise the gain.You don't have X-axis sidelobes and quite large Y-axis ones. Try resizing the reflector ;-) , this should help flatten the radiation pattern and raise the gain (energy from the sidelobes will go into the main direction). The antenna is symmetrical and requires a Balun to connect the coaxial cable. It seems to me that this has nothing to do with the loop antenna (Kharchenko's bi-square), this one can be considered as a broadband dipole with a shunt or as a slot.

One of the simplest options for a balun is to lay a cable along the slot to the zero potential point (connecting the two halves of the emitter sheet) and leading it to the side of the reflector.

But this option requires a relatively small diameter cable, preferably with a TEFLON dielectric and an SMA flange crimped on it. Not everyone has such a cable. it seemed to me that at home it is easier to make the balun suggested by me on the previous page. You can multiply the dimensions in the project by 2.5 - 3 and get the dimensions for the range 1.7-2.7

If you adjust the dimensions, then the structure fits into the perimeter of a metal can with a diameter of 99 mm. This is a very simple and quick solution for home-made from scrap materials.

 

[eco32 27]

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

Edited October 30, 2022 by eco32

[Admin 2545]

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

[eco32 27]

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

[eco32 27]

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?

[Admin 2545]

7 hours ago, eco32 said:

 

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

,,,yes, maybe we should..!!!

[Dr. Pepper 58]

The angle of the box is very important. It influences not only the gain but also swr, bandwith and so on.

[eco32 27]

That's my version of this antenna:

(BOX completely incidental, should be other size)

size

55x38x26cm

bottom : 51x34cm

[Admin 2545]

Eco, the box is very big and has no point, and the biquad antenna is connected like this...

[marcosled86 2]

On 11/2/2018 at 5:00 AM, Admin said:

this file type is not good...??

 

biquad.dxf

biquad.gbr

I just made this antenna and i can only say it works like a charm! and very easy to do.

[eco32 27]

 

Thats the biqaod, is there an chance to achive circular polarisation with two biqoad or biloop antenas using only phase shifter?

(two biquads oriented at 90 degrees to each other)

 

 

[eco32 27]

Add to previous post:
I know that it is possible with dipoles, because there is an opposition phase on the "arms", I have no idea how to do it with a biquad, it has same phase on opostit corners

[Admin 2545]

,,,this works too...!!!

[eco32 27]

In 5GHZ Wifi projects once i saw this twisted construction (I do not know what the reason was, possibly to save space, but maybe something else, I am not able to simulate it yet. But I will make a prototype for measurements)

Thats "normal" biquad and "twisted" biqiad:

Other example of biquod (it's not good to follow him this time), of cours it can not work simultaneously, and MDF as isolator is bad idea.  I think he said something about how this antenna will work in circular polarization. He did not show the chart from the analyzer.

"In this video I show you how to make a biquad antenna that works in the horizontal and vertical simultaneously. This can be of benefit if tracking a constantly shifting object such as a quadcopter. It is also important to note that although the elements in this build are circular (one full wavelength) the biquad still propagates as a linear polarized antenna."

 

 

Edited November 21, 2023 by eco32

[clanon 246]

On 20/11/2023 at 6:41 PM, eco32 said:

Add to previous post:
I know that it is possible with dipoles, because there is an opposition phase on the "arms", I have no idea how to do it with a biquad, it has same phase on opostit corners

it should be possible with a 90 degrees (velocity factor of coax x 1/4 wavelength) between both antennas (but interactions should be simulated)...

[Admin 2545]

,,,SEE THIS...!!!

 

[eco32 27]

20 hours ago, Admin said:

,,,SEE THIS...!!!

Yes, Thank You!!!, it looks like his cross biquad/biloop has 8dBi isted of 10dB from single biquod, without e-field chart it's hard to tell if it's circular polarization in this design there are no phase shifters. In my opinion it has linear polatisation. (I don't have to be right, maybe there is something going on there that I have no idea about)

Just only for Example: S-band circularly polarized crossed dipole antenna for automotive applications

 

[tomasbj 5]

On 5/12/2022 at 5:43 AM, Admin said:

Eco, the box is very big and has no point, and the biquad antenna is connected like this...

I see this antenna is connected to the reflector to the other side of the feeding. Why? and what is the difference between connecting it to ground or not at that end position. Thanks

[clanon 246]

On 11/23/2023 at 0:26 PM, eco32 said:

Yes, Thank You!!!, it looks like his cross biquad/biloop has 8dBi isted of 10dB from single biquod, without e-field chart it's hard to tell if it's circular polarization in this design there are no phase shifters. In my opinion it has linear polatisation. (I don't have to be right, maybe there is something going on there that I have no idea about)

Just only for Example: S-band circularly polarized crossed dipole antenna for automotive applications

 

YES you treat it like a simple dipole (but polarization is 180 degrees inverted for a double quad)

Then to get Circular Polarization , you need to retard 90 degrees the wave at each quarter making a 0 90 180 270 rotation (for this the easiest approach is a Quarter wave length (dielectric in coax included) from One biquad to the other...

 

[clanon 246]

Double lineal here , NOT circular "The polarization of the emitted signal depends on the spatial location of the antenna. Horizontal - horizontal, vertical - vertical polarization. [4] The horizontal position represents when both squares are next to each other, the vertical position is when both squares are placed one above the other."

DoubleBiquadOmni-Antennafor2.4GHzWirelessLinkApplication.pdf

Edited November 28, 2023 by clanon

[eco32 27]

once again:

Dipole has oposit phase on the arms, biquad has same phase on the both ends, trick with phase shiter will not work here.

[clanon 246]

12 hours ago, eco32 said:

once again:

Dipole has oposit phase on the arms, biquad has same phase on the both ends, trick with phase shiter will not work here.

LOOP should be CLOSED at feeding Points...

then , EACH Loop should be feed with 90 degrees phase difference 

Edited November 29, 2023 by clanon

[eco32 27]

No one did it with biquad

 

Edited November 29, 2023 by eco32