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# corporate feed dimensions

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#### cehan

##### Junior Member level 2
hello
i am working on microstrip antenna array for first time...i have problem with designing corporate feed network for 4-patch array...
this problem is how to calculate the width w and length L of each section (z0=50 ohms) and for (z0=70.7 and 100 ohms) also the quarter wave transform.
for example in this figure antenna operate at 10 Ghz
how these dimensions are calculated as seen in this figure

hello
i am working on microstrip antenna array for first time...i have problem with designing corporate feed network for 4-patch array...
this problem is how to calculate the width w and length L of each section (z0=50 ohms) and for (z0=70.7 and 100 ohms) also the quarter wave transform.
for example in this figure antenna operate at 10 Ghz
how these dimensions are calculated as seen in this figure
View attachment 134338

Google "microstrip transmission line calculator" or get the free "txline" calculator from AWR. Rogers corp also has free transmission line calculator.

thanks edf for ur help.i know there is txline that can help..but i am looking for formula
that used to get w and l for corporate feed

There are a series of assumptions here. You are probably trying to create an array of four antennas to radiate in broadside. A corporate feed will have equal total length and a series of power dividers to distribute the input equally among the four antennas. Look into "T junction" dividers, you have three. You might also look into impedance converters (lambda/4 steps) to help connect everything. Mitered corners will probably also be helpful. Microwaves101 dot com is a good place to get help putting this together.

The impedance values you cite suggest a Wilkinson divider. If so that would add complexity to what you are trying to accomplish.

cehan

### cehan

Points: 2
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There are a series of assumptions here. You are probably trying to create an array of four antennas to radiate in broadside. A corporate feed will have equal total length and a series of power dividers to distribute the input equally among the four antennas. Look into "T junction" dividers, you have three. You might also look into impedance converters (lambda/4 steps) to help connect everything. Mitered corners will probably also be helpful. Microwaves101 dot com is a good place to get help putting this together.

The impedance values you cite suggest a Wilkinson divider. If so that would add complexity to what you are trying to accomplish.

thanks Azulykit..i get all useful formula..but there is a small issue. when i am trying to design there are two condition z0 when w/h <1 or w/h>1...the question how i can investigate this while i dont have line width w while i have zo=50 ohm

Patches typically have 130 Ohm impedance (or so) when fed at the edge. The cut-out you show can be used to gradually reduce the impedance to a lower value as you cut into the patch. Zo goes to 0 at the center. Other members have pointed you towards other impedance converters if the above expression is giving you trouble. It looks like you may have a formulation by Wheeler. Look up the reference and it should have the more complete description.

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