What is the difference between powered and non-powered RFID chips (active and passive)?
Active tags have a battery on the tag. The battery may be used to boost read/write range, allow for larger memories, or add sensory and data logging capabilities, such as temperature sensing. Passive tags receive all of their energy from the read/write device that “powers” the tag to allow it to transmit data.

How much memory can a tag have?
Passive tags (non-battery) typically have anywhere from 64 bits to 1 kilobyte of non-volatile memory. Active tags, such as those used in military tags, have memories as high as 128 kilobytes.

How is the information stored on an RFID tag?
The majority of passive tags use EEPROM memory. Some are laser programmed at the silicon level. Many active tags utilize battery-backed SRAM.

How can a passive RFID tag accommodate all the data desired?
It depends on the amount of data required. Some passive tags can store up to 1 kilobyte of data on the tag.

What is the relationship between frequency and tag/antenna distance?
Passive high-frequency (HF, typically 13 MHz) and low-frequency (LF, around 125 kHz) systems typically exhibit a read range of less than 3 feet. With HF and LF tag systems, the size of a tag (and hence area of antenna) will have a significant impact on read range. Some applications limit the read range to around 6 to 8 inches. Some newer technologies (UHF systems) do have a longer read range that can be 20 to 25 feet, but these systems are intended for pallets and shipping crates. Read range depends on many factors, but the size of the transponder’s antenna, the size of the reader’s antenna, and its output power are the main factors to consider. With battery-less transponders, long read range and small size are mutually exclusive.

What are the smallest tags/labels available today?
The smallest smart label form factors are about 1 inch by 1 inch (25 mm square). Specialized RFID tags have been available in sizes as small as 2 mm by 2 mm.

What happens when the printer/encoder encounters a bad tag? How is the operator alerted?
If a Zebra® printer/encoder encounters a bad tag or fails to verify its data, it prints a void error message over the entire face of the smart label. The printer/encoder automatically attempts to program the next tag. Users can select the number of times they want to try to program a good tag. The printer/encoder can then be configured to send an error message to the host.

How durable are the tags? That is, what are the lowest and highest temperatures a tag can withstand?
The typical operating temperature for an RFID inlay (tag) found in most smart labels is between -25º C and 70º C. Storage temperature typically is between -40 º C and 85º C. These values will vary from manufacturer to manufacturer and will depend on the tag’s components. There are industrial tags available in the market that will withstand temperatures as high as 250º C, which could, for example, stand up to heat sterilization requirements for medical items.

Can the UHF tag withstand high-pressure pasteurization?
This would depend on the tag’s construction. Most molded tags can withstand fairly high pressure.

Do X-rays affect tags?
For the most part, X-rays will not affect a tag, but this will depend on the intensity of radiation. Gamma radiation, typically used in sterilization applications, is known to erase or destroy most silicon-based electronic circuits.