Build loop PCB antenna for EM4095 RFID Reader

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mdusan

Joined: 09 Mar 2007
Posts: 5

15 Jun 2007 8:05 em4095

Hi,

I'm building RFID Reader with EM4095 and I want to implement loop PCB antenna. I was wondering if you can give me some guidelines for calculating the copper thickness, track width and width constraint and also number of loops and antenna dimensions.

Can you point me to some literature and calculation tool for building loop PCB antenna.

Thanks in advance.

Best regards,
Dusan Mihajlovic

DrunkBear

Joined: 14 Dec 2006
Posts: 108
Helped: 6
Location: HangZhou,China

21 Jun 2007 7:39 em4095 antenna

i also tried to find some guide for these kind of antenna but in vain.
i suppose the parameters are not that rigid if the loop antenna is only used on near-field occasion because in such case a tiny electromagnetic field could be received by the reader.

mdusan

Joined: 09 Mar 2007
Posts: 5

21 Jun 2007 10:41 em4095.c

Hi,

I suppose that these parameters aren't actually so rigid but i have to calculate antenna L and Q factor in order to calculate values of capacitors needed in the antenna circuit.

Best regards.

mmohdnor

Joined: 23 Aug 2006
Posts: 11

10 Jul 2007 9:59 rfid loop antenna

mdusan, what is the freq of the RFID?

have u found any solution yet?
i'm also trying to design a loop antenna, but it is for remote car key at 433.92mhz.

mdusan

Joined: 09 Mar 2007
Posts: 5

11 Jul 2007 9:22 em4095 problem

Hi,

the antenna frequency is 125KHz. Regarding the solution I didn't succeeded to calculate L and Q factor.

Best regards.

mmohdnor

Joined: 23 Aug 2006
Posts: 11

11 Jul 2007 14:54 calculate pcb antenna

mdusan, are u using any simulation software for the antenna?
(e.g : ADS/Momentum, HFSS, CST, etc)

what is ur current solution as of now? i mean, what have u done so far?
could u tell me more about ur application? (e.g: antenna size, dimension, range, etc)

actually i'm also having about the same problem like u. Still figuring out how to 'load' the antenna. So far what i did is i import the layout structure of the PCB and simulate the S11 of the antenna. Then, I just depend on the simulation software to optimize the value of the R,C, L so that I get the best S11 at my freq, 433.92MHz.

After that, I just test out the antenna with a simple range test. And measure the gain of the antenna.

But currently i'm still not able to simulate the full radiation pattern of the antenna together with lumped components ..

* I use ADS/Momentum, HFSS and a bit of CST..

artem

Joined: 22 May 2003
Posts: 1652
Helped: 91
Location: Turan

11 Jul 2007 15:37 em4095 pcb

there was app note from microchip regarding 13.56 MHz loop antenna for rfid (some empiric calculations to get it done) . As it was suggested - the EM simulation soft can do that . Let say sonnet. I don't know feasibility of this solution as you need many turns due to higher inductance for 125 KHz .

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Joe_User

Joined: 21 Feb 2005
Posts: 40
Helped: 4

12 Jul 2007 13:30 rfid reader antenna dimension

Not sure if this will help, but there is an application note on using sonnet for RFID applications here (there are two entries for RFID under "applications").

mdusan

Joined: 09 Mar 2007
Posts: 5

27 Jul 2007 11:12 em4095 anténa

Hi,

thanks for the information.

mmohdnor wrote:

I didn't used any simulation software. I will download some of the suggested and give it a try. I made a prototype with 16 turn PCB antenna, 20mil track width and 20mil spacing. Dimensions of the outer antenna turn are about the same as standard ISO Card. I'm waiting for the prototype and then I will do some testings and measurement.

Best regards.