For my own education/entertainment, I'm interested in building a RFID reader. But I'm having a problem with a reference to the formula for a rectangular inductor.

This page: https://courses.cit.cornell.edu/ee476/FinalProjects/s2006/cjr37/Website/index.htm

...refers to a variable "b", which is defined as "the width across the conducting part of the coil". I don't understand what that means, since the entire coil conducts. And I couldn't glean the information from that page as their value of 0.3 cm doesn't seem obvious in any of their pictures. What am I missing?

 

For my own education/entertainment, I'm interested in building a RFID reader. But I'm having a problem with a reference to the formula for a rectangular inductor.

This page: https://courses.cit.cornell.edu/ee476/FinalProjects/s2006/cjr37/Website/index.htm

...refers to a variable "b", which is defined as "the width across the conducting part of the coil". I don't understand what that means, since the entire coil conducts. And I couldn't glean the information from that page as their value of 0.3 cm doesn't seem obvious in any of their pictures. What am I missing?

I think the "b" parameter is simply the thickness of the bundle of wires in your coil.

 

I'm pretty sure the thickness of the bundle of wires is represented by variable "h", "the height of the coil". "b" seems to be something else.

 

Great, thanks! Sorry, OBW, if that's that you were referring to. It didn't hit me right away that the bundle has two thicknesses.

 

If you laid the coil flat on a table, b (T in the formula below) would be the height. h is the thickness or width of the bundle. The linked blurb with drawing gives a clear definition.

Formula units are microhenries and inches.








https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwihhKmX8c7OAhWGMSYKHZYVAr8QFgghMAE&url=http://www.minco.com/~/media/Files/Minco/Instructions/Flex%20Circuits/Technical-Specification-FC01.ashx&usg=AFQjCNHKUUHgGN8YZAVNcq9TLrGvTbYYPw&sig2=PiO_kAOiU6iFErG92gtMDQ

 

:thumbs up: