Different types of chips/implants: Stentrode, RFID & NFC
Stentrode (Stent-electrode recording array) is a small stent-mounted electrode array permanently implanted into a blood vessel in the brain, without the need for open brain surgery. It is in clinical trials as a brain-computer interface (BCI) for people with paralyzed or missing limbs, who will use their neural signals or thoughts to control external devices, which currently include computer operating systems. The device may ultimately be used to control powered exoskeletons, robotic prosthesis, computers or other devices.
Stentrode brain chip is implanted within a blood vessel of a patient's brain, along with a power supply and transmitter inserted under the skin in front of the shoulder,
To help paralyzed people regain movement to operate a motorized wheelchair or even a powered exoskeleton. "Researchers in Australia have built an implantable brain-machine interface (BMI) that may give people with spinal cord injuries the ability to walk again using the power of their own thoughts."
RFID (Radio-Frequency Identification) is wireless identification of objects using radio waves. RFID chips that are currently implantable are made up of a non-powered transponder and an antenna that uses power from an RFID reader to operate. This type of RFID that relies on a reader for power is referred as passive, and has a very short range of between near-contact to a few millimeters. Active RFID tags on the other hand, which have their own power, can have a range of up to 100 meters, but all current active RFID tags are too large, expensive, their higher frequencies don't do well with liquids and metal, and their batteries eventually need replacing - and as such they are extremely impracticable to implant.
The implant is a passive device and does not have its own power source (battery). In case your phone runs out of battery, the chip is always accessible to pay wireless with your chip, open doors and it replace different cards and tokens verifying your identity or to share LinkedIn details at networking events.
Many employees use them to get into their office buildings, as a gym pass, to buy food from vending machines, and even instead of using train tickets.
NFC (Near-field Communication) is a type of RFID with a slightly higher frequency (13.56MHz) than a regular passive RFID tag. NFC readers work at a maximum range of about 4 inches (10 centimeters). It has specific standards and protocols set up and owned by the NFC Forum that allow for it to function both as a tag and a reader - a feature most used for peer-to-peer communication for secure data exchange between devices like NFC-capable smartphones. In this regard, NFC is more IoT-adaptable than regular passive RFID, more so as NFC-capable devices will use other associated tech like bluetooth and WiFi to facilitate two-way information sharing.