FreeLists / si-list / [SI-LIST] Re: PCB Trace Antenna

[Istvan Novak <istvan.novak@xxxxxxx>]

Boopathy,

if my memory serves me correctly, around 1uH inductance
can be achieved with a single turn of about 0.6 meters in 
diameter.  For your application this clearly suggests multiple
turns.  So you probably need to place the turns along the
perimeter of the card, to make the loop as big as possible. 
The number of turns can be determined as soon as you know
 the inductance of a single turn: you can look it up in text books.
 If you dont have one handy, do a Google search on inductance
of circular or rectangular loops.  The specified inductance gives
you the tuning capacitance you need to put in parallel, and the
50-ohm termination will set your Q, so you have those all set
 for you.  Looking at recommended placements and layouts as
Andrew suggested, would be helpful.

Regards,
Istvan

Boopathy J. wrote:

>Dear Istvan,
>   I need to Create an PCB trace antenna of 
>F=13.5Mhz, Impedence=50 ohms, L=1.2uH.
>
>Now I need to determine PCB trace length (end to end), width of the trace
>etc. Is there is any calculator available to determine it?.
>
>Right Now we have a plan to complete the placement & routing of the board
>which will lie inside the loop antenna. Is it a right design to do it?? 
>
>Otherwise, I need to Make two separate PCB (one for component & another one
>for loop antenna). 
>
>Regards,
>Boopathy J
>
>
>-----Original Message-----
>From: Istvan Novak [mailto:istvan.novak@xxxxxxx] 
>Sent: Thursday, September 22, 2005 5:19 PM
>To: Boopathy J.
>Cc: si-list@xxxxxxxxxxxxx
>Subject: Re: [SI-LIST] PCB Trace Antenna
>
>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 =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
>>
>>
>>    
>>

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