Low-Power RFED Wake-Up Receiver Design for Low-Cost Wireless Sensor Network Applications

The development of wake-up receivers (WuR) has recently received a lot of interest from both academia and industry researchers, primarily because of their major impact on the improvement of the performance of wireless sensor networks (WSNs). In this paper, we present the development of three different radiofrequency envelope detection (RFED) based WuRs operating at the 868 MHz industrial, scientific and medical (ISM) band. These circuits can find application in densely populated WSNs, which are fundamental components of Internet-of-Things (IoT) or Internet-of-Everything (IoE) applications. The aim of this work is to provide circuits with high integrability and a low cost-per-node, so as to facilitate the implementation of sensor nodes in low-cost IoT applications. In order to demonstrate the feasibility of implementing a WuR with commercially available off-chip components, the design of an RFED WuR in a PCB mount is presented. The circuit is validated in a real scenario by testing the WuR in a system with a pattern recognizer (AS3933), an MCU (MSP430G2553 from TI), a transceiver (CC1101 from TI) and a T/R switch (ADG918). The WuR has no active components and features a sensitivity of about −50 dBm, with a total size of 22.5 × 51.8 mm2. To facilitate the integration of the WuR in compact systems and low-cost applications, two designs in a commercial UMC 65 nm CMOS process are also explored. Firstly, an RFED WuR with integrated transformer providing a passive voltage gain of 18 dB is demonstrated. The circuit achieves a sensitivity as low as −62 dBm and a power consumption of only 528 nW, with a total area of 634 × 391 μm2. Secondly, so as to reduce the area of the circuit, a design of a tuned-RF WuR with integrated current-reuse active inductor is presented. In this case, the WuR features a sensitivity of −55 dBm with a power consumption of 43.5 μW and a total area of 272 × 464 μm2, obtaining a significant area reduction at the expense of higher power consumption. The alternatives presented show a very low die footprint with a performance in line with most of the state-of-the-art contributions, making the topologies attractive in scenarios where high integrability and low cost-per-node are necessary.

Bio-Inspired Cell Concentration and Deformability Monitoring Chips

The paper presents a couple of biofluidic devices, whose functions are inspired from biological cell concentration and deformability monitoring functions. The cell concentration monitoring chip is inspired from RBC control mechanism in kidney, performing cell concentration monitoring functions. The cell deformability chip, inspired from selective RBC destruction mechanism in spleen, performs mechanical cell deformability monitoring functions. The structures and principles of the bio-inspired chips are presented and compared with those of the biological organs. The unique features and performance characteristics of the bio-inspired chips are analyzed and verified from experimental study. The bio-inspired cell concentration monitoring chips perform flow-rate insensitive concentration measurement, while the bio-inspired cell deformability monitoring chips achieve size-independent cell deformability measurement. Common advantages of the bio-inspired chips include simple structures, digital signals and high integrability, thus making them suitable for use in integrated digital biomedical systems.

Bio-Inspired Cell Concentration and Deformability Monitoring Chips

The paper presents a couple of biofluidic devices, whose functions are inspired from biological cell concentration and deformability monitoring functions. The cell concentration monitoring chip is inspired from RBC control mechanism in kidney, performing cell concentration monitoring functions. The cell deformability chip, inspired from selective RBC destruction mechanism in spleen, performs mechanical cell deformability monitoring functions. The structures and principles of the bio-inspired chips are presented and compared with those of the biological organs. The unique features and performance characteristics of the bio-inspired chips are analyzed and verified from experimental study. The bio-inspired cell concentration monitoring chips perform flow-rate insensitive concentration measurement, while the bio-inspired cell deformability monitoring chips achieve size-independent cell deformability measurement. Common advantages of the bio-inspired chips include simple structures, digital signals and high integrability, thus making them suitable for use in integrated digital biomedical systems.

First-Principles Approach to Mn-Doped Group IV Semiconductors: Comparison with Experiments and Outlook

We present an extensive theoretical and experimental study of the Mn-Ge dilute magnetic semiconductor, a material which - due to its high integrability with mainstream Si technology - may hold good promises for spintronic applications. Ab-initio calculations on several different systems containing isolated Mn impurities as well as small clusters (up to three Mn impurities) show that Mn has a tendency to segregate into the Ge matrix and to stabilize occupation of interstitial sites if these are coordinated with other Mn occupying substitutional sites nearby. Several different experimental characterizations (HRTEM, XRD, UPS, MOKE) performed on Mn ion-implanted systems are analyzed and discussed: a close comparison betweeen experimental evidences and density functional calculations allows a full understanding of the sample properties and to disentagle the contributions coming from the diluted and segregated phases. The complexity of this system shows that much has to be done still to understand the physics of these materials and to undisclose all their possible applications.