RFID 125kHz antenna Design

The ARRL Handbook or one of their other publications has information on Low Freq. antennas, design and construction.

See: <http://www.arrl.org/>

Your post was a little difficult to understand. It seemed that you are desiring to construct an antenna capable of operating at 125kHz and you wanted to do it in a format of 1 meter by 1 meter. Is that correct?

I'm not sure what you meant by "470H antenna, etc.

In any case, here is some input to consider. Wavelength at 125kHz (not considering velocity factor in the material) is 2400 m (7,874 ft). A vertical 1/4 wave radiator would be on the order of 2000 ft high. Not impossible, but a major undertaking.

DX hobbyists in Finland who are interested in monitoring medium wave AM commercial radio stations (wavelength on the order of 300 m or about a 1000 ft) do so with several miles of "long wire" structure--basically looks like a telephone line oriented broadside to the part of the earth they are interested in.

Government installations used for communicating with submarines used similar arrays and lots of power according to things I have read. This is not personal knowledge on my part.

Successful communication down in these regions of the spectrum has been accomplished using two grounded rods driven in the earth and relying on the ground wave propagation exclusively. I know about this being done at audio frequencies and above. These used the ground rods placed much closer than wavelength distances and were reasonably effective over short distances.

You can receive the 125kHz signal on almost anything probably including the springs under your mattress--if the source is close enough or powerful enough--but if you intend to transmit, the antenna must load the transmitter correctly. It must be impedance matched to the transmitter and have a resonant mode at the operating frequency. Traditional designs basically use a long wire of some sort to accomplish this.

That's what I know about it. Good Luck.

Lonnie

Hello sir,

I am paramasivan from india .I am doing my final year engineering in India. Now i am in my final semester doing my project.I saw ur reply in CR4.

I am now working in the area of RFID.I am in need of any one complete RFID Tag desing circuit with circuit diagram for my project work . So can u provide me with any one sample RFID Tag circuit Diagram... please sir, because i have to finish my project work within two weeks.. please send me any one such a sample circuit as soon as possible to my mail ID : parampp1986@gmail.com ..or send me the web site link,where complete RFID tag Circuit diagram is avialable...

with Regards,

paramasivan

parampp1986@gmail.com

Hello sir,

I am paramasivan from india .I am doing my final year engineering in India. Now i am in my final semester doing my project.I saw ur reply in CR4.

I am now working in the area of RFID.I am in need of any one complete RFID Tag desing circuit with circuit diagram for my project work . So can u provide me with any one sample RFID Tag circuit Diagram... please sir, because i have to finish my project work within two weeks..

please send me any one such a sample circuit as soon as possible to my mail ID : parampp1986@gmail.com ..or send me the web site link,where complete RFID tag Circuit diagram is avialable...

with Regards,

paramasivan

parampp1986@gmail.com

how can I built a 125khz RFID Antenna?

my email address is amir_seyedan@hotmail.com

I think in this design something like the ones used to control animals.

I attach one RFID chip into the animal to be monitored and I want to know which animal crose the door.

Something like that.

I need a cheap antenna that I can develop with staff I can find at home or at least close to my city.

Thank you for you answer.

470 H is the impedance that the reader is asking for to the antenna will be attached to it.

Saludos!

Delmar

Here's a good starting point

http://ww1.microchip.com/downloads/en/AppNotes/00710c.pdf

Best Wishes