Current loop matching filter optimization...

I have a current loop "antenna" (design supplied by the customer) that's
tuned to, guess, 50R


C2 L
----+----||----UUUUU----.
| |
| |
=== C1 R esr
| R
| |
GND GND


The esr resistance and L inductance are the current loop plus some added
resistance.

Now the environment is somewhat uncontrolled (conductors,...) and the
inductance is allowed to change quite a bit (circa 5%) which plays bad
games with the matching and I'm trying to find some design that limit
input sensitivity to the L parameter.

Since the smith plot with the distance to the perturbing conductors as
the parameter almost retraces the frequency plot I had a look into
wideband matching (Bode-Fano,...) but I now think this leads no where...

I guess this pb has been addressed by the RFID guys or possibly MRI too
but can find no useful hint.

Any info/hint/link/idea is welcomed...

 

probably more in this that you ever wanted to know.

http://books.google.dk/books/about/...l_and_Biome..html?id=to_3sGPIBQQC&redir_esc=y



-Lasse

 

a écrit :

Thanks, I'll have a look.