How to design your antenna?

SpringCard OEM NFC/RFID module is suggested with a 69x45mm antenna which covers a wide diversity of uses.

Some situations may lead to the design of a specific antenna, it could be for facing clutter constraints or to optimise communication with nonstandard cards (bigger or smaller ones). 

But designing an antenna is not an easy task !

You need to tune it but also to test and validate your antenna that is an expert job.

SpringCard has created this small guide for those who want to develop this skill. 

Development Steps

 

The first step to take when designing your own antenna is to determine the expected volume of

operating range with cards and tags that you will use.

You will also make sure to respect norms and protocols for your antenna to be compatible with most of the mobile entities, but if you limit yourself to a specific objects format you will be able to some extent to depart from these norms.

Either way you will respect field levels and antenna symmetry in order to respect the EMC constraints (electromagnetic compatibility).

The environment in which your antenna is placed will have an impact on its performances.

It is better to avoid placing the antenna nearby an electronic equipment radiating around 13.56MHz.

The antenna should be taken away from any conductive surface that blocks waves (Faraday cage) or that disperse waves as heat (Foucault current).

In a few words: beware of metal surfaces !

The use of ferrite channels waves which reduces the risk, but this works only under a certain limit.

At last, it is needed to measure the antenna characteristics once placed in its permanent environment

(resonance frequency, current circulating in the coil) and realise the last tuning to obtain the

waveforms imposed by norms and respect the operating range of SpringCard product. 

 

And for those of you who want to save time and have the insurance of a design made by an expert, SpringCard designs specific antennas for its clients on a regular basis. Contact us !

Published on 1/5/2018