Alessandro Finocchiaro

A 90-nm CMOS 5-Mbps Crystal-Less RF-Powered Transceiver for Wireless Sensor Network Nodes

This paper presents a 90-nm CMOS batteryless transceiver for RF-powered wireless sensor networks. The circuit is made up of a RF energy harvesting module that is implemented through a multi-stage rectifier, a power management unit, and a PLL-based RF front-end that enables TX carrier synthesis by exploiting the RF input signal as a reference frequency. This avoids the use of a local crystal oscillator, thus implementing a highly integrated low-cost wireless transceiver. An active narrowband transmission scheme is adopted with the aim of overcoming the reader self-jamming that limits the operating range of backscattering-based RF-powered devices. The circuit supports a 915-MHz FSK downlink and a 2.45-GHz OOK uplink, while achieving a data rate up to 5 Mbps. It operates with an RF input power as low as -17.1 dBm.

A 90nm CMOS 5Mb/s crystal-less RF transceiver for RF-powered WSN nodes

In this work, a batteryless CMOS RF transceiver for WSN nodes is presented. It includes a fully functional receiver for symmetrical RX/TX throughput and exploits narrowband active transmission to improve the uplink reading range without burdening the reader complexity. A PLL-based architecture is adopted both to recover incoming data and synthesize the TX carrier from the input RF signal. This enables crystal-less operation, thus minimizing the system com- plexity and cost.

A 900-MHz RFID system with TAG-antenna magnetically-coupled to the die

A novel UHF-RFID system which employs a magnetic coupling between the die of a TAG and its external antenna is presented. With respect to the state-of-the-art, the proposed solution avoids the physical connection between die and antenna, thus significantly improving TAG reliability while reducing assembling costs. Thanks to the integrated spiral, on-wafer wireless testing can be performed thus greatly reducing testing costs. Moreover, the arrangement exploiting the TAG-antenna and its interface to the IC is well-suited to be implemented in a low-cost roll-to-roll process by using conductive inkjet on any dielectric material.

An RF-powered FSK/ASK receiver for remotely controlled systems

A fully integrated RF-powered receiver for remotely controlled systems is presented. The receiver adopts ASK and FSK modulations and is capable of operating in the ISM bands of 433 MHz, 869 MHz, and 915 MHz, while achieving a bit rate down to 62 kb/s. The circuit includes an RF harvester and a power management unit for the RF to DC power conversion and control, respectively, and an OTP memory with a digital interface for the operating configuration. Measurements show a harvester sensitivity of -18.8 dBm and accurate ASK demodulation with a modulation index as low as 10%. The current consumption is 87 μA and 720 μA for the ASK and FSK receiving mode, respectively. The circuit was fabricated in a 0.13-μm CMOS technology and occupies a core area of 2.2 mm2.

An over-the-distance wireless battery charger based on RF energy harvesting

An RF powered receiver silicon IC (integrated circuit) for RF energy harvesting is presented as wireless battery charger. This includes an RF-to-DC energy converter specifically designed with a sensitivity of −18.8 dBm and an energy conversion efficiency of ∼45% at 900 MHz with a transmitting power of 0.5 W in free space. Experimental results concerned with remotely battery charging using a complete prototype working in realistic scenarios will be shown.