It really depends on whether you plan to make a bunch of these or if you are
just making one. If you are just making one, I'd suggest a sample kit of
inductors as the easiest thing to do.

PCB coils are straightforward to do, but they take up board space and they
will need some tweaking to get the right dimensions (Translates to PCB
spins). If you factor in the additional board size, it may be cheaper to use
a coil.

The other problem with PCB Coils in production is that if you get in a new
batch of PCB material, your inductance could well shift, since the
inductance is dependent on the board dielectric constant.

Dave

On 5/10/07, Gerhard Fiedler <lists@connectionbrazil.com> wrote:
>
> Hello,
>
> I'm working on a transmitter and receiver in the 400MHz range. The
> inductors in that frequency range are really small (tens of nH) and I
> thought that buying such an inductor may not make much sense. So I looked
> into PCB and air core inductors. Here's what I found so far:
>
> <http://www.educypedia.be/electronics/electroniccalculatorcomp.htm> Lots
> of
> links to all kinds of calculator sites.
>
> <http://emcsun.ece.umr.edu/new-induct/> Inductor calculations for all
> kinds
> of geometries, but not PCB spirals.
>
> <http://smirc.stanford.edu/spiralCalc.html> Calculator for integrated
> spiral inductors; may work for PCB inductors also, but I don't know what
> they assume in terms of what's around the conductor.
>
> <http://tinyurl.com/2rn89n> A paper by Marc T. Thompson listing a number
> of
> formulas for PCB and wire coils.
>
> <http://www.freelists.org/archives/si-list/11-2001/msg00109.html> Steve
> Rogers, who seems to have done some work with PCB inductors, lists a
> number
> of sources of information and describes some of the potential problems
> with
> PCB inductors.
>
>
> Has anybody experience with PCB inductors? Or maybe even with a
> formula/calculator that yields realistic results? Are simple air core
> inductors much easier to get right?
>
> Thanks,
> Gerhard
>
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