This is a three part series covering the three main pieces to an RFID system: 

Three main Components:

Hardware (1/3)     
Middleware (2/3)     
Back - End Software (3/3)


Hardware (1/3):
The hardware is the RF - analog side to the RFID system.  It is here where the tag information will be read and sent to the interrogator for analysis.

Readers:

Readers handle the tags and also manage the power, number of reads, and also I/O's that may be added to the system.

Readers come in many flavors and the right reader is a preference to the application’s needs.

- - An ALIEN 9800 reader is being used for my RFID project - -

Tags:

There are many ways to read and represent an RFID tag, and the technology continues to grow and advance.  The fundamental ways to read a tag is to have the tags passively or actively perform.  The active tag is equipped with an internal power source as to transmit who it is when it is needed.  The passive approach may use power from the reader, or could also manipulate the readers signal as to distinguish its identity.  Class 1 Generation 2 tags are a newer more secure class for tagging.

- - Class 1 Generation 2 is being used in the project - -

Antennas:

Antennas are what send and receive the RF information.  Most systems use at least two antennas to handle the transmitting and receiving.  The pattern of the antennas transmission and reception is design to get the most reads for the amount of power being used; providing the largest reception band possible.  The most popular pattern is a circular pattern, to create a spherical zone of interrogation.