Chip-Less and Battery-Less Subharmonic Tags for Wireless Sensing with Parametrically Enhanced Sensitivities and Dynamic Ranges

Abstract

Massive deployments of wireless sensor nodes (WSNs) that continuously detect physical, biological or chemical parameters are needed to truly benefit from the unprecedented possibilities opened by the Internet-of-Things (IoT). Just recently, new sensors with higher sensitivities have been demonstrated by leveraging advanced on-chip designs and microfabrication processes. Yet, WSNs using such sensors require energy to transmit the sensed information. Consequently, they either contain batteries that need to be periodically replaced or energy harvesting circuits whose low efficiencies prevent a frequent and continuous sensing and impact the maximum range of communication. Here, we report a new chip-less and battery-less tag-based WSN that fundamentally breaks any previous paradigm. This WSN, formed by off-the-shelf lumped components on a printed substrate, can sense and transmit information without any need of supplied or harvested DC power, while enabling full-duplex transceiver designs for interrogating nodes rendering them immune to their own self-interference. Also, even though the reported WSN does not require any advanced and expensive manufacturing, its unique parametric dynamical behavior enables extraordinary sensitivities and dynamic ranges that can even surpass those achieved by on-chip sensors. The operation and performance of the first implementation of this new WSN are reported. This device operates in the Ultra-High-Frequency range and is capable to passively and continuously detect temperature changes remotely from an interrogating node.

Reflective Parametric Frequency Selective Limiters with sub-dB Loss and $μ$Watts Power Thresholds

“…Driven by the need of developing a new class of passive open-loop phase noise cleaners, known as parametric filters [21], [22], our group has recently investigated the stability of large-signal periodic regimes in diode-based 2:1 parametric frequency dividers (PFDs [23]), even describing a new design methodology to achieve exceptionally low parametric power thresholds (P th ) in lumped or distributed on-board PFD implementations. By further exploiting the outcomes of this investigation, we recently developed a new battery-less, chip-less and harvester-free sensor tag [24], referred to as subharmonic tag (SubHT), utilizing a 860 MHz diode-based parametric circuit made of lumped off-the-shelf components assembled on a printed substrate. Through the SubHT, we demonstrated that the proper engineering of the dynamics of diode-based parametric circuits permits to achieve extraordinarily low P th values (-18 dBm for an input frequency of 860 MHz) approaching the power threshold attainable by SoA ferritebased FSLs, even when relying on low quality factor (<80) components and on packaged diodes with junction capacitance in the pF -range.…”