Background: This paper aims to complement the latest contribution in the literature that provides estimates of physiological parameters of a dynamic model for the elbow time profile during walking while linking them to a neurodegenerative disorder (Parkinsons’s disease) characterized by motor symptoms. An upper limb model is here proposed in which an active contractile element is included within a model, viewing the arm as a double pendulum system and muscles as represented by a Kelvin–Voight system. All model parameters characterizing both the shoulder and the elbow of each subject are estimated via a gradient-like identifier whose exponential convergence properties are determined by a non-anticipative Lyapunov function, ensuring robustness features. Methods: Joint angle data from different walking subjects (healthy subjects and patients with Parkinson’s disease) have been recorded using an IMU sensor system and compared with the joint angles obtained by means of the proposed model, which was adapted to each subject using available anthropometric knowledge and relying on the estimated parameters. Results: Experiments show that the reconstruction of shoulder and elbow time profiles can be definitely achieved through the proposed procedure with the estimated stiffness parameters turning out to constitute objective and quantitative indices of muscle stiffness (as a pivotal symptom of the pathology), which are able to track changes due to the therapy. Conclusions: The same dynamic model is actually able to capture the main features of the upper limb movement of both (healthy and pathological) walking subjects, with its parameters, in turn, characterizing the nature and progress of the pathology.

This paper presents a solid state power amplifier (PA) at 24 - 28 GHz in a 0.15-mu m GaN on SiC technology. The PA adopts single-ended architecture containing power and a driver stages based on common source topology to get an output power and a gain greater than 32 dBm, and 20 dB, respectively. Harmonic balance(HB) simulations are performed to optimize the single-ended PA for wideband characteristics. Optimum stability and matching networks are introduced to meet the desired characteristics. The performance of the PA is experimentally characterized and a good co-relation between simulation and measurement is found. The PA shows a peak small-signal gain of 21.5 dB at 26 GHz. In terms of large-signal excitation, the PA delivers a maximum output power greater 32dBm at 26 GHz with peak PAE of at least 36%. The PA demonstrates high output power without power combining and it occupies an area of 4 mm(2). The PA is suitable for various applications targeting frequency band of 24-28 GHz.

This paper presents a novel design approach to enhance the performance of the Peaking branch of a Doherty Power Amplifier (DPA), by properly manipulating its input harmonics through a suitable nonlinear driver stage. In particular, aiming to implement a Class F harmonic termination for the final stage, a third harmonic voltage component is injected at its input with a driver, so that the phase of the third harmonic current at the output of the final stage is reversed with respect to its normal evolution, allowing a Class F design strategy for a class C biased device. The design strategy is described together with the design and experimental characterization of a prototype for X-Band application. The DPA is realized on the 120 nm gate-length GaN-on-SiC technology available at WIN Semiconductors. The MMIC provides more than 36 dBm and 40% of output power and efficiency, respectively, at 10 GHz.

Parkinson’s disease (PD) is responsible for a broad spectrum of signs and symptoms, including relevant motor impairments generally rated by clinical experts. In recent years, motor measurements gathered by technology-based systems have been used more and more to provide objective data. In particular, wearable devices have been adopted to evidence differences in the gait capabilities between PD patients and healthy people. Within this frame, despite the key role that the upper limbs’ swing plays during walking, no studies have been focused on their harmonic content, to which this work is devoted. To this end, we measured, by means of IMU sensors, the walking capabilities of groups of PD patients (both de novo and under-chronic-dopaminergic-treatment patients when in an off-therapy state) and their healthy counterparts. The collected data were FFT transformed, and the frequency content was analyzed. According to the results obtained, PD determines upper limb rigidity objectively evidenced and correlated to lower harmonic contents.

Parkinson's disease (PD) is a chronic neurodegenerative disorder with high worldwide prevalence that manifests with muscle rigidity, tremor, postural instability, and slowness of movement. These motor symptoms are mainly evaluated by clinicians via direct observations of patients and, as such, can potentially be influenced by personal biases and inter- and intra-rater differences. In order to provide more objective assessments, researchers have been developing technology-based systems aimed at objective measurements of motor symptoms, among which are the reduced and/or trembling swings of the lower limbs during gait tests, resulting in data that are potentially prone to more objective evaluations. Within this frame, although the swings of the upper limbs during walking are likewise important, no efforts have been made to reveal their support significance. To fill this lack, this work concerns a technology-based assessment of the forearm-swing capabilities of PD patients with respect to their healthy counterparts. This was obtained by adopting a viscoelastic model validated via measurements during gait tests tackled as an inverse dynamic problem aimed at determining the torque forces acting on the forearms. The obtained results evidence differences in the forearm movements during gait tests of healthy subjects and PD patients with different pathology levels, and, in particular, we evidenced how the worsening of the disease can cause the worsening of the mechanical support offered by the forearm's swing to the walking process.

In this paper, the experimental verification of suitable input harmonic injection to achieve class F operating conditions in class $\mathbf{C}$ (under pinch-off) biased active devices is discussed. In detail, it is demonstrated that by generating a third harmonic component $V_{g, 3}$ with a proper phase relationship with respect to the fundamental one $V_{g, 1}$, it is possible to change the phase of the resulting output harmonic components, and in particular of the third one $I_{D, 3}$, thus generating the proper squaring of the output voltage. Experimental results at device level have shown an improvement in terms of output power and efficiency from 2.24W to 3.00W and from 72.2% to 79.3%, respectively. The proposed approach could play a key role in the maximization of the achievable efficiency of Doherty power amplifiers, where the auxiliary branch needs to be biased in class C for a exploitation of the architecture.

This contribution presents the activities carried out towards the realization of a high-power solid state power amplifier, based on Gallium Nitride (GaN) technology, targeting more than 125W of output power in the frequency range 17.320.2 GHz, conceived for the next generation K-band Very High Throughput Satellites (vHTS). For this purpose, specific Monolithic Microwave Integrated Circuits (MMICs) Power Amplifiers (PAs) were developed on a commercially available 100 nm gate length GaN on Silicon (GaN-Si) process (OMMIC process D01GH). The design was carried out considering space reliability constraints on electrical parameters and accounting for the spacecraft temperature limits, which are extremely challenging for this technology, to keep the junction temperature of all devices below $160^{\circ}\mathrm{C}$ in the worst-case condition (i.e., maximum environmental temperature of $85^{\circ}\mathrm{C})$. The final MMIC, based on a three-stage architecture, demonstrates on wafer and in pulsed condition to achieve a minimum output power and power added efficiency (PAE) of 10W (40dBm) and 35% (with a peak of 45%) in the full Ka-band satellite downlink, i.e., from 17.3 GHz to 20.2 GHz. The packaged version demonstrates in continuous wave (CW) conditions an output power larger than 39.5dBm with a PAE better than 30%. Moreover, long-term (24h) CW test at saturated output power has shown almost negligible performance degradation, thus providing confidence in the robustness of the selected GaN-Si technology.

Objective: In order to evaluate Parkinson disease patients' response to therapeutic interventions, sources of information are mainly patient reports and clinicians' assessment of motor functions. However, these sources can suffer from patient's subjectivity and from inter/intra rater's score variability. Our work aimed at determining the impact of wearable electronics and data analysis in objectifying the effectiveness of levodopa treatment. Methods: Seven motor tasks performed by thirty-six patients were measured by wearable electronics and related data were analyzed. This was at the time of therapy initiation (T0), and repeated after six (T1) and 12 months (T2). Wearable electronics consisted of inertial measurement units each equipped with 3-axis accelerometer and 3-axis gyroscope, while data analysis of ANOVA and Pearson correlation algorithms, in addition to a support vector machine (SVM) classification. Results: According to our findings, levodopa-based therapy alters the patient's conditions in general, ameliorating something (e.g., bradykinesia), leaving unchanged others (e.g., tremor), but with poor correlation to the levodopa dose. Conclusion: A technology-based approach can objectively assess levodopa-based therapy effectiveness. Significance: Novel devices can improve the accuracy of the assessment of motor function, by integrating the clinical evaluation and patient reports.

Early noninvasive reliable biomarkers are among the major unmet needs in Parkinson's disease (PD) to monitor therapy response and disease progression. Objective measures of motor performances could allow phenotyping of subtle, undetectable, early stage motor impairments of PD patients. This work aims at identifying prognostic biomarkers in newly diagnosed PD patients and quantifying therapy-response. Forty de novo PD patients underwent clinical and technology-based kinematic assessments performing motor tasks (MDS-UPDRS part III) to assess tremor, bradykinesia, gait, and postural stability (T0). A visit after 6 months (T1) and a clinical and kinematic assessment after 12 months (T2) where scheduled. A clinical follow-up was provided between 30 and 36 months after the diagnosis (T3). We performed an ANOVA for repeated measures to compare patients' kinematic features at baseline and at T2 to assess therapy response. Pearson correlation test was run between baseline kinematic features and UPDRS III score variation between T0 and T3, to select candidate kinematic prognostic biomarkers. A multiple linear regression model was created to predict the long-term motor outcome using T0 kinematic measures. All motor tasks significantly improved after the dopamine replacement therapy. A significant correlation was found between UPDRS scores variation and some baseline bradykinesia (toe tapping amplitude decrement, p = 0.009) and gait features (velocity of arms and legs, sit-to-stand time, p = 0.007; p = 0.009; p = 0.01, respectively). A linear regression model including four baseline kinematic features could significantly predict the motor outcome (p = 0.000214). Technology-based objective measures represent possible early and reproducible therapy-response and prognostic biomarkers.

In this contribution it is reported the design, implementation and characterization of a 4-stage single-ended Ka-band power amplifier based on 100nm GaN/Si commercial process. The amplifier, designed for CW radar applications, has been measured under small-signal and pulsed large-signal conditions. The amplifier exhibits an output power above 4W, together with power added efficiency in excess of 28% and operative gain larger than 25 dB over the 34 GHz- 38 GHz frequency range.

Healthy and pathological human walking are here interpreted, from a temporal point of view, by means of dynamics-on-graph concepts and generalized finite-length Fibonacci sequences. Such sequences, in their most general definition, concern two sets of eight specific time intervals for the newly defined composite gait cycle, which involves two specific couples of overlapping (left and right) gait cycles. The role of the golden ratio, whose occurrence has been experimentally found in the recent literature, is accordingly characterized, without resorting to complex tools from linear algebra. Gait recursivity, self-similarity, and asymmetry (including double support sub-phase consistency) are comprehensively captured. A new gait index, named Φ-bonacci gait number, and a new related experimental conjecture-concerning the position of the foot relative to the tibia-are concurrently proposed. Experimental results on healthy or pathological gaits support the theoretical derivations.

This paper presents the design of a D-band frequency quadrupler (FQ) based on two cascaded frequency doublers. Each doubler relies on the bootstrapped Gilbert cell (GC) mixers. The FQ is developed with a standard 130-nm SiGe BiCMOS process. It consists of fully integrated input and output baluns, frequency doublers, and matching networks. The design of the FQ was optimized via single-ended matching networks to reduce the chip area and increase bandwidth. The results based on the EM-simulation of FQ with the assistance of the hicum model for the transistor, demonstrate a peak conversion gain and output power of 25 dB and 5 dBm, respectively at 130 GHz. The FQ shows a 3-dB bandwidth higher than 84 GHz with an n th harmonic rejection of at least 16 dBc. The FQ can be exploited in various systems design for different D-band applications. The future work includes measurement of the FQ.

This paper presents the design of a balanced power amplifier (PA) using a 130-nm SiGe BiCMOS process. The PA consists of three stages, each based on cascode topology. The design of the PA was optimized using low-Q matching networks for the D-band applications. The results based on EM-simulation of the PA, with assistance of vbic and hicum models for the transistor, demonstrate an average peak gain of 26.5 dB with the 3-dB bandwidth higher than 80 GHz. In terms of large-signal, the PA provides an output power and PAE larger than 14 dBm, and 4 percent, respectively, in the D-band. Moreover, it provides an output power greater than 13 dBm at 110-190 GHz. The PA is highly suitable to drive frequency multipliers for the development of broadband sub-THz signal sources. The future work includes measurement of the PA.

BACKGROUND:Technology-based objective measures (TOMs) recently gained relevance to support clinicians in the assessment of motor function in Parkinson's disease (PD), although limited data are available in the early phases. OBJECTIVE:To assess motor performances of a population of newly diagnosed, drug free PD patients using wearable inertial sensors and to compare them to healthy controls (HC) and differentiate different PD subtypes [tremor dominant (TD), postural instability gait disability (PIGD), and mixed phenotype (MP)]. METHODS:We enrolled 65 subjects, 36 newly diagnosed, drug-free PD patients and 29 HCs. PD patients were clinically defined as tremor dominant, postural instability-gait difficulties or mixed phenotype. All 65 subjects performed seven MDS-UPDRS III motor tasks wearing inertial sensors: rest tremor, postural tremor, rapid alternating hand movement, foot tapping, heel-to-toe tapping, Timed-Up-and-Go test (TUG) and pull test. The most relevant motor tasks were found combining ReliefF ranking and Kruskal- Wallis feature-selection methods. We used these features, linked to the relevant motor tasks, to highlight differences between PD from HC, by means of Support Vector Machine (SVM) classifier. Furthermore, we adopted SVM to support the relevance of each motor task on the classification accuracy, excluding one task at time. RESULTS:Motion analysis distinguished PD from HC with an accuracy as high as 97%, based on SVM performed with measured features from tremor and bradykinesia items, pull test and TUG. Heel-to-toe test was the most relevant, followed by TUG and Pull Test. CONCLUSIONS:In this pilot study, we demonstrate that the SVM algorithm successfully distinguishes de novo drug-free PD patients from HC. Surprisingly, pull test and TUG tests provided relevant features for obtaining high SVM classification accuracy, differing from the report of the experienced examiner. The use of TOMs may improve diagnostic accuracy for these patients.

This paper reports the design, manufacturing and test of a power amplifier, based on a newly power bar device developed on GaN technology, conceived for L-Band applications. The realized active device is a single 10mm active periphery GaN HEMT, realized by paralleling eight 1.25 mm-gate periphery devices (10x125 μm), fabricated on a 0.5 μm GaN-on-SiC technology by Leonardo company. The power amplifier realized with this device is tested in pulsed condition, demonstrating an output power higher than 40 W at 30 V of drain voltage supply, with an associated efficiency of 50 % at 3 dB of gain compression.

This paper presents the design of a single-ended power amplifier (PA) based on a 130-nm SiGe BiCMOS process with the fmax of 500 GHz. The PA comprises of three stages, with each stage based on cascode topology. The design was optimized to obtain a peak gain of 30 dB with 3-dB bandwidth larger than D-band (110-170 GHz) and peak output power higher than 12 dBm. The simulation results show that the PA can provide average peak gain of 30 dB with 3-dB bandwidth of 90 GHz. In terms of large-signal, it provides output power and PAE larger than 12 dBm, and 5%, respectively, at 115-180 GHz. Moreover, it provides an output power greater than 10dBm at 105-200 GHz. The PA is highly suitable for the development of broadband sub- THz signal sources. The future work includes measurement of the PA.

A wideband 4-way combined power amplifier (PA) in a 0.13-μm BiCMOS process is presented. The overall PA is based on four unit cells of 3-stage cascode PA, which is adopted for larger output power and higher gain. Load pull simulations are done to optimize the unit cells together with the 4-way combiner for wideband characteristics. With the assistance of hicum and vbic models, the overall PA shows a peak gain of 30dB at 126GHz with the 3-dB bandwidth higher than 80GHz. Under large-signal excitation, the PA delivers a maximum output power greater than 17.5dBm at 120-180 GHz with peak PAE higher than 5%. The PA can be used for various future D-band applications. Measurements are on the way and will be presented into the final contribution.

This paper presents a 4-way combined G-band power amplifier (PA) fabricated with a 130-nm SiGe BiCMOS process. First, a single-ended PA based on the cascode topology (CT) is designed at 185 GHz, which consists of three stages to get an overall gain and an output power higher than 27 dB and 13 dBm, respectively. Then, a 4-way combiner/splitter was designed using low-loss transmission lines at 130-210 GHz. Finally, the combiner was loaded with four single-ended PAs to complete the design of a 4-way combined PA. The chip of the fabricated PA occupies an area of 1.35mm2. The realized PA shows a saturated output power of 18.1 dBm with a peak gain of 25.9 dB and power-added efficiency (PAE) of 3.5% at 185 GHz. A maximum output power of 18.7 dBm with PAE of 4.4% is achieved at 170 GHz. The 3-dB and 6-dB bandwidth of the PA are 27 and 42 GHz, respectively. In addition, the PA delivers a saturated output power higher than 18 dBm in the frequency range 140-186 GHz. To the best of our knowledge, the power reported in this paper is the highest for G-band SiGe BiCMOS PAs.

Tetraplegic people need continuous assistance in every daily activity. Assistive technologies can improve, to a certain degree, their quality of life allowing partial autonomy with powering their residual capability of movements. In this work, we propose a novel wire-free low-cost user-friendly battery-operated sensory headwear, which allows home automation controlled by head movements. The headwear is equipped with an inertial measurement unit (IMU), a low power microcontroller and a transmission module to measure, condition and wireless transmit data related to head movements. Such a sensory headwear allows the subject, simply by head movements, either to select one computer icon among an ensemble or to select one actuator, among a number of others. Each icon and each actuator drive a specific physical action in a home or work environment. We devoted particular efforts to increase the battery autonomy, by means of radio frequency energy harvesting solutions, for lasting operational mode. The harvester, based on commercial chipsets, was optimized in the 2.4-2.5 GHz range to exploit headwear itself radiated energy and environmental energy, in particular from Wi-Fi and Bluetooth surrounding devices. An average efficiency, calculated as output to input power ratio, of around 60% at -5dBm input power level has been obtained. (C) 2019 Elsevier GmbH. All rights reserved.