RFID systems use radio frequency transmission to identify, catalog or locate items, which can primarily be objects, but also people or animals. The reader contains electronic components that release and receive a signal to and from the proximity tag, a microprocessor that checks and decodes the received data and a memory that records the resulting data, which will later be transmitted further if necessary. To enable the reception and transmission of data from the tag, the reader has an antenna connected. The antenna can be integrated into the reader housing or it can be separated, located away from the rest of the electronics. As with most radio frequency applications, to obtain good performance the diameter of the antenna must be relatively large!