Sorry if my question may seem simple, but I discover the plans of an antenna (RECTANGULAR COIL WITH MULTILAYER) and I can not identify b and h on this given schema,

x = width of coil
y = length of coil
b = width of cross section
h = height (coil build up) of cross section

enter image description here

Here are the three possibilities that I see, The first one that seems to me to be the good one: enter image description here

The second that could be as valid: enter image description here

and finally the thirteenth which could be valid too but in this one there would be no 'depth' or thickness so I doubt that it is the right one: enter image description here

Do the circles in the rectangle of the section represent wires ?

Where are b and h ?

What is the direction of 'coil build-up' ?

Thank you for your help.

  • \$\begingroup\$ It would probably help if you cite where you found this information. \$\endgroup\$
    – Tyler
    Commented Aug 17, 2019 at 16:08

1 Answer 1


Probably these dimensions are used to calculate the inductance by an approximation formular.

Wheeler's formular is likely used as it's often referenced when searching for such a respective approximation formular.

Then \$b\$ is:

enter image description here

And for \$h\$ you can think of printing that picture several times and placing the sheets one onto the other.

Here are also links of two sites applying wheeler's formular with isometric view pictures:

http://www.rfcafe.com Multi-Layer Air-Core Inductance

  • \$b \, @rfcafe \$ is \$h \, @your\, picture\$
  • \$c \, @rfcafe \$ is \$b \, @your \, picture\$


  • \$l \, (length of coil) \, @allaboutcircuits \$ is \$h \, @your\, picture\$
  • \$c \, (thickness of coil)\, @allaboutcircuits \$ is \$b \, @your \, picture\$

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