[SOLVED] How to calculate the feed line in phase array antennas using IE3D?

[guytoub]

hi everybody!

I'm trying to built a phase array microstrip antennas at 2.45 Ghz with four elements.
the desing is made with IE3D and i would like to know how i can calculate the feed line to have a Z of 50Ω.

thanks a lot
[/b]

 

[shameemkabir]

Re: Phase array antennas

It depends on the kind of feed you are using.

If you know the input impedance of the patches, you can simulate the feed with different width of the feedline to get 50 ohm at the feed input.

decide what kind of feed network you want to use (e.g., corporate feed). Then replace the patch antenna with equivalent resistor (since you want to calculate only the return loss). Do the simulation in IE3D (or ADS momentum) to get the input impedance at the input. Change the width of the feedline until you get 50 ohm. Sometimes with one thickness of the line, it is difficult to achieve desired result. In that case you need to use quarter wave transformer. Finally replace the resistors with patches to finalize your design.

 

[guytoub]

Re: Phase array antennas

thank for your answer.

1°) my problem is to find the right input impedance of the patch; i think i don't a have the good method with IE3D.

2°) for my patch, in found an input impedance of 217Ω and i would like to know if i use one feedline to get 50Ω ( the with of the feedline is two small) or if i use quater wave line ?

in the case i use one feedline it is necessary to have a length of λ/2 for my feedline?


if you have a tutorial or any examples it will be good.

thanks a lot.

 

[shameemkabir]

Re: Phase array antennas

As I told earlier, input impedance of your array depends on the type of feed you are using. In your case, if it is possible to use corporate feed for your system, you will get input impedance close to 50 ohm I guess (since you 4 elements with 217 ohm each).

Microstip antenna by Bahl and Bhatia is a good book for your reference.

 

[freqzt]

Re: Phase array antennas

hi everybody!

I'm trying to built a phase array microstrip antennas at 2.45 Ghz with four elements.
the desing is made with IE3D and i would like to know how i can calculate the feed line to have a Z of 50Ω.

thanks a lot
[/b]

It's quite easy to calculate the feed impedance. You can use txline from h++p://www.appwave.com. You can download it from this site.

btw, to bulit a phased array microstrip antenna do you use butler matrix or another method? Please tell me, I want to know it.

 

[guytoub]

Re: Phase array antennas

i'm a begginer so, i design one patch an after only, a try to made an array.

i've got Linecalc or appcad to calculate the feedlie but my problem is how to determinate the impedance of antenna at F0.