4x4 1700/2700 feed

[jbckdsav 7]

65 cm dish CST simulation.

 

[Admin 2545]

for which antenna ... ???
where is Harry36's original drawing ... ???

[Admin 2545]

,, these would be the dimensions ...

PCB material double plated FR4 #0.5mm

[jbckdsav 7]

Good!!!

[Harry36 140]

On 05.02.2022 at 10:09, jbckdsav said:

65 cm dish CST simulation.

 

 

Due to the deviation of the phase center of the antenna from the focus of the mirror, the direct direction of the beam from the mirror deviated. All 4 beams will eventually be directed in different directions. It's not good at all. it is not intended for feed.

[jbckdsav 7]

There is very very little deviation.

[clanon 246]

something is OFF , i think it is SPILLING signal OUTSIDE the dish , maybe with some wall side box...or a RIM...

[Harry36 140]

 

19 hours ago, clanon said:

something is OFF , i think it is SPILLING signal OUTSIDE the dish , maybe with some wall side box...or a RIM...

I figured out what's wrong

When the reflector was added to my project, it was not coaxial to the stern and the offset angle was not observed.

Because of this, the deviation on the first port is almost zero.

 

 

Edited February 7, 2022 by Harry36

[Harry36 140]

 

3.

 

4

Edited February 7, 2022 by Harry36

[jbckdsav 7]

Another way to do it could be to use such.

https://www.mdpi.com/2072-666X/12/4/383

 

 

[Admin 2545]

Compact Dual-Band MIMO Antenna System

,,,it might work, but I think it would need a reflector...

 

CDB MIMO.cst

[jbckdsav 7]

very interesting.

[Admin 2545]

,,,with reflector...

[jbckdsav 7]

Here my small test similar result.

[Harry36 140]

On 16.01.2023 at 5:10 PM, jbckdsav said:

Here my small test similar result.

 

 

Whatever the shape of the emitters, we still will not get a single phase center for the emitter to place it in the focus of the offset reflector.

Leaving the focus of the phase center of the antenna will lead to a deviation of the radiation pattern beam from the main direction (this can be seen on the graphs: the beam deviates from the axis), this can be minimized by pressing the emitters to each other.
as soon as we start to press the emitters to each other, then the isolation between the power ports begins to fall.
if you carefully consider the article to which you refer, then on the graphs we will see the parameters S12, S13, S14. this is the isolation. she is on the verge of a foul. -10 is very little. the smaller the isolation between the power ports, the more difficult it is for the modem to parse the received signal. this results in slower speeds due to reduced modulation. There is such a document of one fairly authoritative organization in which engineers recommend having an isolation between power ports of at least -15 dB, although they say that it will most likely work at -8.
how it will work, they do not say. (fig.3)

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwj29t-_gc_8AhUX6CoKHbbTDhAQFnoECAcQAQ&url=https%3A%2F%2Fwww.infineon.com%2Fdgdl%2FInfineon-AN214810_Antenna_Placement_Guidelines_For_2_2_MIMO_WLAN-ApplicationNotes-v03_00-EN.pdf%3FfileId%3D8ac78c8c7cdc391c017d0d27bb9962ec&usg=AOvVaw1Jgfoq-zGhnt_rMzvrDVj7

well done, nice simulation! but do not repeat the mistakes of other users. for the overall picture in the initial calculation, it is necessary to show other users the graphics: 1. gain - this will allow you to understand how the antenna behaves in the desired range. 2. SWR. this gives the concept of a matched antenna in the original band. the SWR graph should be displayed in the range, or a little wider, to show others the margin of the antenna. the graph is displayed from 1, not from 0, as some do. don't make childish mistakes. SWR cannot be less than 1. The output of the graph from 0 is an indicator of the developer's illiteracy. 3. radiation patterns, at the borders and in the middle of the range. this makes it possible to evaluate the distortion at different frequencies.

p.s.

you also need to understand that for different types of offset or direct-focus reflectors, you need to have different amplification of the irradiator.
for F/D<=0.5, the gain should be about 10 dBi. for a ratio of ~=0.7, the gain should be about 12 dBi. these parameters are valid for any frequency and this is clearly seen from the factory feeds designed for different types of reflectors.

good luck

 

[jbckdsav 7]

needs test realworld with 4x4 BTS.