A fundamental theory of coupled line coupler-based negative group delay (NGD) topology is established in this paper. The microwave circuit under study consists of the isolated-and coupled-accesses connected in a feedback loop through a lossy interconnect line. The NGD topology is built with fully distributed elements. The S-parameter model is formulated in order to derive the NGD optimal values, cutoff frequencies, and bandwidth. Thus, the NGD existence condition as a function of the coupling coefficient and the feedback interconnection attenuation is demonstrated and examined. Hence, the fundamental characteristics of the coupler-based NGD topology are described. In order to verify the feasibility of the theory, NGD prototypes were designed, fabricated, and measured. The implemented one- and two-stage microstrip circuits have NGDs of about -2.3 and -4 ns, respectively, at 1.26 GHz. The reflection coefficients are better than 10 dB and the insertion losses are, respectively, about 2.4 and 4.3 dB. The developed NGD topology, fully constructed with distributed elements without any lumped components, is particularly beneficial in terms of design simplicity. The proposed NGD circuit might find potential application in microwave signal delay correction.

An innovative theory on the passive circuits capable to generate low‐pass negative group delay (NGD) behaviour is introduced. An identification method enabling to identify the first‐order NGD simple cells built with resistor‐inductor (RL)‐ and resistor‐capacitor (RC)‐networks is elaborated. The fundamental characteristics as the NGD level and cut‐off frequency are formulated from the low‐pass NGD circuit canonical transfer function. The NGD existence conditions are derived in function of the established topology parameters. Despite the attenuation systematically related to the passive cell nature, low‐pass NGD behaviours with tens ns NGD level and tens MHz bandwidth were obtained with an example of lumped RL‐network‐based L‐topology circuit. Transient analysis was performed to illustrate that the NGD phenomenon enables to exhibit baseband signal advance effect. The proposed NGD topology simplicity promises their potential applications especially in term of signal correction and the modern electronic system improvement.

Population aging and increasing pressure on health systems are two issues that demand solutions. Involving and empowering citizens as active managers of their health represents a desirable shift from the current culture mainly focused on treatment of disease, to one also focused on continuous health management and well-being. Current developments in technological areas such as the Internet of Things (IoT), lead to new technological solutions that can aid this shift in the healthcare sector. This study presents the design, development, implementation and evaluation of a platform called Common Recognition and Identification Platform (CRIP), a part of the CareStore project, which aims at supporting caregivers and citizens to manage health routines in a seamless way. Specifically, the CRIP offers sensor-based support for seamless identification of users and health devices. A set of initial requirements was defined with a focus on usability limitations and current sensor technologies. The CRIP was designed and implemented using several technologies that enable seamless integration and interaction of sensors and people, namely Near Field Communication and fingerprint biometrics for identification and authentication, Bluetooth for communication with health devices and web services for wider integration with other platforms. Two CRIP prototypes were implemented and evaluated in laboratory during a period of eight months. The evaluations consisted of identifying users and devices, as well as seamlessly configure and acquire vital data from the last. Also, the entire Carestore platform was deployed in a nursing home where its usability was evaluated with caregivers. The evaluations helped assess that seamless identification of users and seamless configuration and communication with health devices is feasible and can help enable the IoT on healthcare applications. Therefore, the CRIP and similar platforms could be transformed into a valuable enabling technology for secure and reliable IoT deployments on the healthcare sector.

This paper develops an innovative method of sensors time-delay suppression. The proposed delay cancellation technique is highlighted with a theoretical concept and time-domain experimental demonstrations by using negative group delay (NGD) function. The analytical investigation is elaborated with an NGD topology constituted by a simple active RC-network. It is established theoretically that this active cell behaves like a low-pass NGD topology. The synthesis equations enabling to calculate the NGD cell parameters as a function of the desired NGD and gain are formulated. Frequency-and time-domain analyses showing the NGD function in multi-time scale are discussed. The NGD function verification is fulfilled with the design and fabrication of a proof-of-concept prototype. Nano-, micro-and milli-seconds NGD effects are numerically and experimentally proved. As expected, time-domain experimental demonstrations showing arbitrary waveform signal in outstanding time-advance are realized. Moreover, the feasibility of the signal delay cancellation with 1-m and 8-m length cables is experimented. The developed NGD time-delay cancellation demonstrations open the potential applications for the sensor performance improvement.

The signal distribution interconnect network modeling plays an important role during the digital/mixed printed circuit board (PCB) design. With the increase of the design complexity, the PCB interconnect modeling becomes a challenging task. This paper proposes an innovative circuit theory of the PCB electrical interconnects modeling based on the tensorial analysis of network (TAN). The model under study, fundamentally built with the Kron–Branin formalism, is applied to the asymmetrical 1:3 Y-Y-tree interconnects. This Kron–Branin method enables to establish quickly the tree interconnects equivalent model for the signal integrity (SI) analysis. An asymmetrical microstrip circuit was designed and fabricated to validate the developed TAN concept. The modeled, simulated, and measured S-parameters are in good agreement in the broad frequency band 0.1 MHz to 8 GHz. The electrical power budget distributed through the Y-Y-tree prototype in dc and in the considered entire frequency band was analyzed. Furthermore, the Kron–Branin model was also validated in the time domain with 1-Gb/s-rate 8-bits serial data and eye diagram analyses. This innovative formalism presents a considerably high computation speed and is beneficial for the SI analyses thanks to its adaptability to the complex system.