The NFC Technology was first introduced into smartphones in September 2011 and is now widely integrated into most phones, whether they are iOS or Android based.
An NFC-enabled smartphone uses an NFC controller chip connected to an NFC antenna.
The controller chip can be defined as a specialized Central Processor Unit which accepts instructions provided by the application processor software and then processes those instructions to complete the NFC tag detection and/or reading NFC tag content.
The NFC smartphone antenna can be positioned either on the top, middle, or bottom of the back side of the phone, and it is rarely indicated on the phone case.
Recent smartphones tend to embed their NFC antenna at the top of the device.
Touchpoint connection and smartphone interaction
During an interaction, the tag’s antenna picks up both the necessary energy to operate and an external signal provided by the smartphone and activates the tag (NFC touchpoint) by means of electromagnetic induction between the two antennas.
Thanks to a tiny embedded processing unit and some memory, the tag analyzes the query, processes it, and replies to the messages received from the smartphone.
The communication range between the smartphone and a tag is in the order of a few centimeters.
Among the five NFC Forum tag types, Type 5 tags (variant of the ISO/IEC 15693 vicinity standard) provide the best range of them all, as they have been defined to operate at the best possible distance.
For the best NFC user experience, the use of Type 5 tags is strongly recommended.
For brand recognition applications, ST recommends using the ST25TV, as an NFC Forum certified Type 5 chip.
Smartphone NFC range
So, what can you expect in terms of range? There are many smartphone models with the built-in NFC function, including premium smartphones and most of the mid-range models on both Android and iOS platforms.
Different smartphones have different NFC reading areas and ranges. This is due to the following factors:
- Antenna positioning
- Antenna size and quality
- Effect of nearby components
- Different power levels
The best position for a smartphone to read an NFC tag is different from one model to the next. Different smartphones with the same applications may exhibit distinct behavior and performance levels.
NFC smartphone scanning delay
Even when NFC is enabled, a phone is not continuously checking for nearby NFC tags. Instead, it checks periodically if there are any NFC tags nearby waiting to be read.
This is not related to the tag technology but inherent to each and every single phone; there are no rules, the checking interval depends on several different factors including manufacturer preferences, operating system, power settings, other background applications taking up processor time, and many more.
The NFC implementation is smartphone-dependent and can be very different from one device to the other. This has a direct impact on the user experience.
What kind of information can be exchanged?
NFC tags can contain two different types of data:
NDEF format (NFC Data Exchange Format)
The first type of data is called NDEF (NFC Data Exchange Format) information, as normalized by the NFC Forum. NDEF formatted content is fully managed by NFC smartphones and can trigger a dedicated response from smartphones such as launching a browser to open a specific web page (URL), calling or texting a given telephone number, or adding a new contact to the phone’s directory.
Proprietary with dedicated content formatting
The second type is proprietary with dedicated content formatting, which in this case would require a dedicated mobile app to interact with the tag.
For example, if the tag embeds a NDEF-coded URL, the smartphone will automatically open a web browser to the target webpage. In case of a tag with proprietary commands, an NFC mobile application is needed to take best advantage of all tag features.