rfid system guidelines?

Hi Poster,

Your description is somewhat general. Generally spoken, you should take into account things like: orientation of objects, type of label, RF environment close to and far from the tagged objects, available hardware (and frequency bands), etc.

The most difficult thing (in the UHF applications that I saw) is to guarantee detection in a certain zone (for example 99.8%), but to guarantee no detection in other zones. This is because of multi path propagation. In a multi path environment the coverage of the RFID system is like the "plot" of a (full) paint can falling from the stairs. For some applications you can get better results with multiplexers (so you have, for example, 4 antenna outputs).

Implementing an RFID application is a (long) discussion / trade-off between functional requirements and technical possibilities/ limitations. In many cases you need to change constructions, add things, to create the correct environment for a good functioning system. It may also affect working procedures.

When you talk about a multi reader environment, you may also experience reader to reader interference. Sometimes a multiplexing scheme may help (in combination with frequency planning), but this reduces number of reads/sec.

When you are participating in a project, be very careful when guaranteeing figures. You need at least to understand RF propagation, RF measurement and the protocol that is used.

As you mentioned "metallic products" you need labels specially prepared to give some reasonable performance when mounted on metallic objects. When metallic objects are close and adjacent to each other (label in between) performance will drop significantly. I assumed that you are talking about UHF 800-900 MHz systems.

Best regards,

Wim PA3DJS