Boopathy It sounds like you are making a smartcard reader antenna. These are normally tuned circuits as Istvan mentioned. Therefore, your resonance frequency will depend on the loop inductance and your chosen parallel capacitance. Once the size and the Q of the circuit have been decided you know what inductance you ideally want. Then you can decide whether you have a single or multiple turn loop. If you look in the ISO standards for RFID / smartcards then there are several examples of standard reader circuits. Presumably, your reader will have to be ISO compliant anyhow, so they are worth a look at. Regards Andrew Boopathy, :Not knowing the RF system parameters you have :to achieve, just based on the stated frequency, :you probably want to create a tuned loop antenna. :In this case the trace impedance matters less, :in fact you may want to increase it as much :as possible. More will matter the size :(and orientation) of loop and the number of turns. :regards, :Istvan novak :SUN Microsystems Boopathy J. wrote: >Content-Type: text/plain; > charset="us-ascii" >Content-Transfer-Encoding: quoted-printable >HI, > > We are designing HF card Reader at f =3D 13.56MHZ. > >we need to implement the Antenna In PCB traces. As I haven't worked = >much on > >RF PCB design, I would like to know how to implement it & > >how to determine the Trace length & impudence for 13.56MHz. > >=20 > >=20 > >Thanks In advance > >=20 > >Regards, > >Boopathy J > >=20 > > > > > ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu