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Looking for documents about Phase Array Antenna

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xilinx

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Phase Array Antenna

Hi every body

I need some document and application in "Phase Array Antenna", eny body can help me?

thanks
 

cross

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I have seen certain documents in MCU fileman.

Regards
Cross
 

jamez

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:D What degree document you need? If foundmental, I suggest U look for
special book.
 

Lupin

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Hi Shou,
do you know what code can be used to make analysis or sinthesis of Phased array.
I use PCAAD, Ensemble, Asap but I'ld like other codes (not e-m I mean).

Thanks in advance

Lupin
 

egliu

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Re

do you need account for coupling between elements
 

jamez

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yes,should count for coupling between elements and also deal with element unmatch when it phase scan in the array.
 

Lupin

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At the beginning, I can need a code neglecting mutual coupling....
I wrote a code in MatLab and I want to check it. What software can you suggest me?

Thanks Lupin
 

flatulent

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mutual coupling

The mutual coupling will have the greatest effects on input impedance. The coupling will be least for certain spacings of the elements. The mutual impedance can be broken into real and imaginary parts that cycle and decline as the separation increases. They are out of phase by about a quarter wave.

At a quarter wave the mutual impedance is 30 -j40. at a half it is -12 -j30. At 1.1 wave it is 10 +j10.
 

egliu

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re

some yesrs ago, I used NEC to simulate teh coupling coeficent for a conformal array. you can try it.
 

dowjones

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I dont think that nec or any other code accounts for the mismatch occurring when scanning the antenna beam (scan blindness). I suggest you to read the papers of Pozar (and others) on the scan blindness phenomena and make your own code neglecting coupling. If it is not too strong (<25dB) in practice most people neglects the coupling effects. Of course you should address and confirm that couplings are low enough
 

egliu

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Re

I am afraid that I can not agree with dowjones, In some very simple cases, you can neglect the coupling. but for a lower sidelobes antenna design, it is impossible to design as that.
 

dowjones

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hi egliu,

I agree with you that if couplings can be taken into account the fabricated antenna would be much more similar to the synthesized one.

However take into account the following
1) an antenna design with low sidelobes requires many elements in the array, and if the coupling terms are considered, the problem maybe almost imposible to solve (just in terms of computing resources)
2) in a low sidelobe antenna the excitation errors/uncertainties maybe much more important than coupling terms
3) ideally the synthesis should be done with embedded element patterns (measured to be realistic), which already account for the effect of the coupling, estructure, edge effects,..., although unfortunately implies that you have to build the antenna before
4) many text books (antenna handbook by Lo, microwave scanning antennas by Hansen,...) already include element excitations for low sidelobe array which do not account for coupling and are good starting points for the synthesis

I agree with you that it is better include the couplings, but there are many more effects that should be also taken into account that it is almost impossible to cope all of them. I'm afraid that we still have to wait for a software tool which definitely solves all our problems.
 

flatulent

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one method

Here is one method of reducing coupling. Start with a pair of elements and phase and space them so that there is a null in the plane of the elements. Use these element pairs as new elements in an array. Since the element pairs do not put energy in the direction of the others, they will couple less.

If you have a two dimensional array, you do pairs of pairs to get the nulls in all directions of the plane before building up the whole antenna array.
 

egliu

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Re

hi dowjones

I must say that it is the most important thing to know coupling coefficent in designing a lower sidelobe antenna. Let me tell you what I have done before. We need not conside all element in you simulation, just two of them, change the position of elements, you can get their coupling coefficent. then you can synthisis an antenna distribution according taylor or other distribution function. we built a conformal array with -40 db sidelobe some years ago, measurment proves this way is possible.

thanks and regards
 

Timelord

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Phased arrays

I have some phased array papers from IEEE (scanned)

Can upload if you wish?


Timelord
 

Lupin

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Thanks TimeLord,
the IEEE papers are welcome. I've just to check my own code about array antennas in Matlab.. so if you need something about it, please ask.

Regards
Lupin

Main Interests
Phased arrays, micorstrip,stripline,WG compoennts, microstrip (slotted) antennas.
 

Timelord

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Phased Array Papers

OK, give me a day or so and i'll upload some stuff for you.

I only have a dial up connection so be patient.



Timelord
 

Lupin

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Are you involved in the study of phased arrays?
Do you know a deidcated code for analysis and optimization except for PCAAD or LINPLAN?
I've to check the validity of my own code...

thanks for the articles
Lupin
 

Dderijken

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Does Anybody in here can explain how a
3-bit diode is used (& how it works) on
phasing the array antennas .

Regards,
dderijken
 

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