Near field antenna design

Thread Starter

Nano001

Joined Jan 12, 2010
101
Hi everyone, I have an OOK signal with a carrier frequency of 20 MHz and I am looking to design an interfacing transmitter antenna. Given that the wavelength is 15 meters, a 1/4 wavelength antenna would be much too large for my application. I am wondering if a near field antenna, similar to what is used for RFID, would give me a couple meters read range at this frequency, given the antenna was driven with enough power and designed correctly. A design methodology similar to the below pdf is what I am thinking, but for 20 Mhz.

http://www.st.com/st-web-ui/static/...ical/document/application_note/CD00221490.pdf
 

DickCappels

Joined Aug 21, 2008
10,180
It would if you make the antenna large enough and have a suitable transmitter and receiver.

20 MHz might not be the best frequency to use. In the United States, that frequency is used for standard time and frequency transmission. 13.56 MHz ± 7 kHz is reserved for Industrial, Scientific, and Medical use in most of the world and would using that frequency would lessen your chances of interfering with another service.
 

Thread Starter

Nano001

Joined Jan 12, 2010
101
Ok thanks for the replies. I have some experience to carry this out but of course input from the experts would be a great help. I am aware of the 13.56 MHz band but I am not sure how much control I will have over the frequency. Knowing that it can be done is a good start for me.
 
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