The widespread deployment of the Internet of Things (IoT) requires the development of new embedded systems, which will provide a diverse array of different intelligent functionalities. However, these devices must also meet environmental, maintenance, and longevity constraints, while maintaining extremely low-power consumption. In this work, a batteryless, low-power consumption, compact embedded system for IoT applications is presented. This system is capable of using a combination of hybrid solar and radiofrequency power sources and operates in the 900MHz ISM band. It is capable of receiving OOK or ASK modulated data and measuring environmental data and can transmit information back to the requester using GFSK modulated data. The total consumption of the system during its sleep state is 920nW. Minimum power required to operate is 15.1dBm or 70 lux, when using only radiofrequency or solar powering, respectively. The system is fully designed with components off the shelf (COTS).

This paper presents the development of two dual-band radio-frequency (RF) harvesters optimized to convert far-field RF energy to DC voltage at very low received power. The first one is based on a patch antenna and the second on a dipole antenna. They are both implemented on a standard FR4 substrate with commercially off-the-shelf devices. The two RF harvesters provide a rectified voltage of 1 V for a combined power, respectively, of −19.5 dBm at 915 MHz, −25 dBm at 2.44 GHz, of −20 dBm at 915 MHz, and −15 dBm at 2.44 GHz. The remote powering of a clock consuming 1 V/5 µA is demonstrated, and the rectenna yields a power efficiency of 12%.

The widespread deployment of the Internet of Things requires new embedded systems providing functionality with extremely low power consumption. This paper presents a battery-less, low-power consumption, compact embedded system using remote RF powering with COTS (Components Off The Shelf), and OOK or ASK based data communications, operating in the 900 MHz band.