We present a self-sustained battery-less multi-sensor platform with RF harvesting capability down to −17 dBm and implementing a standard DASH7 wireless communication interface. The node operates at distances up to 17 m from a 2 W UHF carrier. RF power transfer allows operation when common energy scavenging sources (e.g., sun, heat, etc.) are not available, while the DASH7 communication protocol makes it fully compatible with a standard IoT infrastructure. An optimized energy-harvesting module has been designed, including a rectifying antenna (rectenna) and an integrated nano-power DC/DC converter performing maximum-power-point-tracking (MPPT). A nonlinear/electromagnetic co-design procedure is adopted to design the rectenna, which is optimized to operate at ultra-low power levels. An ultra-low power microcontroller controls on-board sensors and wireless protocol, to adapt the power consumption to the available detected power by changing wake-up policies. As a result, adaptive behavior can be observed in the designed platform, to the extent that the transmission data rate is dynamically determined by RF power. Among the novel features of the system, we highlight the use of nano-power energy harvesting, the implementation of specific hardware/software wake-up policies, optimized algorithms for best sampling rate implementation, and adaptive behavior by the node based on the power received.

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This paper presents an integrated peripheral unit interfaced to an embedded Phase-change Memory (ePCM) macrocell, with the aim of adding Analog In-memory Computing (AIMC) feature without any modifications to the internal structure of the memory array. The testchip has been designed and manufactured in a 90-nm STMicroelectronics CMOS technology. The unit allows the execution of signed Multiply and Accumulate (MAC) operations at the edge of the memory array exploiting the physical characteristics of memory devices. I-V characteristic non-linearity and transconductance time drift of PCM cells are overcome through a regulated bitline readout circuitry with time-coded inputs, along with a drift compensation technique based on a conductance ratio. Measurements results show 1-σ accuracy of 95.56% in MAC operations, whose decrease in time is roughly negligible at room temperature and is less than 1% after 24 hours at 85°C bake.

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This paper presents an Analog Front-End for integrated Wake-Up Radios. The proposed Analog Front-End is composed of an envelope detector, a Schmitt trigger and a biasing block and has three distinctive features: i) clockless solution, which does not require an always-on oscillator; ii) an envelope detector with band-pass response which leads to smaller capacitance, thus easier integration, and low-frequency noise suppression; iii) temperature compensated biasing scheme. An active scheme for the detector is used based on MOSFETs operated in the subthreshold region with a self-biased topology. Advantages and drawbacks of the proposed architecture are analyzed. A prototype was fabricated in the STMicroelectronics 90-nm BCD technology. The overall power consumption, excluding the biasing block, is 36 nW at 1.2 V. A 10 -3 Bit Error Rate is measured with a 771-MHz, 2-kbit/s OOK modulated input signal with -46 dBm power at room temperature and at -20 °C, and with almost -43 dBm power at 60 °C.