An Embedded Inductive Coupling Transceiver for Internet of Things Applications

A low-complexity transceiver circuit for wireless communications through inductive coupling is presented here. This transceiver is fully passive (obtaining its power from a nearby reader) and therefore, it is suitable for IoT applications that require a wireless means of communications while avoiding periodic battery re-charging. The simplicity of the transceiver circuit makes it attractive for low-cost sensing solutions. Communication between the transceiver and a reader (uplink) is achieved using load-shift keying or backscatter modulation, while communication between a reader and the transceiver (downlink) is accomplished amplitude-shift keying. In both cases, data is formatted using an asynchronous serial format. The transceiver was implemented using off-the-shelf components. A small $8\ \text{mm}\times 10.8\ \text{mm}$ printed circuit board including the transceiver, a microcontroller and a sensor was fabricated. The performance of the uplink was assessed at different distances between the antennas and at a maximum rate of 2 Mbps. It was found that at 2 Mbps, a bit error rate of $9.07\times 10^{-4}$ can be achieved.