Hello
I am trying to design a unique EAS system and need some help with the antenna design
I have a rx and tx PCB boards. On the 8.2MHz I am using soft tags that are flat

What I want to do is very specifically control how wide the antenna detection area is.
I want it to be a very narrow plain yet cover a specific size.
More specifically I have an opening that is 6 feet wide by 4 feet tall. The wall is wood wall however the opening is made of 2 inch steel square tube and I basically want the antenna signal to work inside this steel frame area
As our products pass through this I want the system to activate. But because our system uses a production line it stops frequently. Which is the problem. Only the red area in the picture below I want to be the detection area.

I want it to go off only when the device crosses this line at the 6x4 opening. I want it as exact as possible. But not wider. Because if a device stops say 2 inches before this line I don’t want it to activate.
So my question is
-how would I make this antenna design to work?
-what gauge and type of wire?
- what can I do so the detection is only inside this square area and not on the sides but directed only in the box?
-do I shield the antenna on the side I don’t want it?
I attached my EAS PCB boards as well as a basic drawing of what I am trying to do.




If you can help with specifics to my design or what to do I would appreciate it.
... I did some chances for you ]
I am trying to design a unique EAS system and need some help with the antenna design
I have a rx and tx PCB boards. On the 8.2MHz I am using soft tags that are flat

What I want to do is very specifically control how wide the antenna detection area is.
I want it to be a very narrow plain yet cover a specific size.
More specifically I have an opening that is 6 feet wide by 4 feet tall. The wall is wood wall however the opening is made of 2 inch steel square tube and I basically want the antenna signal to work inside this steel frame area
As our products pass through this I want the system to activate. But because our system uses a production line it stops frequently. Which is the problem. Only the red area in the picture below I want to be the detection area.

I want it to go off only when the device crosses this line at the 6x4 opening. I want it as exact as possible. But not wider. Because if a device stops say 2 inches before this line I don’t want it to activate.
So my question is
-how would I make this antenna design to work?
-what gauge and type of wire?
- what can I do so the detection is only inside this square area and not on the sides but directed only in the box?
-do I shield the antenna on the side I don’t want it?
I attached my EAS PCB boards as well as a basic drawing of what I am trying to do.




If you can help with specifics to my design or what to do I would appreciate it.
[Mod Note: - as per Harald's comments, it is very important to always use the correct notation
Last edited by a moderator: