Circuit Configuration Research Articles

Multiband Microstrip Rectenna Using ZnO-Based Planar Schottky Diode for RF Energy Harvesting Applications.

This paper presents a single-substrate microstrip rectenna for dedicated radio frequency energy harvesting applications. The proposed configuration of the rectenna circuit is composed of a clipart moon-shaped cut in order to improve the antenna impedance bandwidth. The curvature of the ground plane is modified with a simple U-shaped slot etched into it to improve the antenna bandwidth by changing the current distribution; therefore, this affects the inductance and capacitance embedded into the ground plane. The linear polarized ultra-wide bandwidth (UWB) antenna is achieved by using 50 Ω microstrip line and build on Roger 3003 substrate with an area of 32 × 31 mm2. The operating bandwidth of the proposed UWB antenna extended from 3 GHz to 25 GHz at -6 dB reflection coefficient (VSWR ≤ 3) and extended from both 3.5 to 12 GHz, from 16 up to 22 GHz at -10 dB impedance bandwidth (VSWR ≤ 2). This was used to harvest RF energy from most of the wireless communication bands. In addition, the proposed antenna integrates with the rectifier circuit to create the rectenna system. Moreover, to implement the shunt half-wave rectifier (SHWR) circuit, a planar Ag/ZnO Schottky diode uses a diode area of 1 × 1 mm2. The proposed diode is investigated and designed, and its S-parameter is measured for use in the circuit rectifier design. The proposed rectifier has a total area of 40 × 9 mm2 and operates at different resonant frequencies, namely 3.5 GHz, 6 GHz, 8 GHz, 10 GHz and 18 GHz, with a good agreement between simulation and measurement. The maximum measured output DC voltage of the rectenna circuit is 600 mV with a maximum measured efficiency of 25% at 3.5 GHz, with an input power level of 0 dBm at a rectifier load of 300 Ω.

COVID, Co-Ventilation, and Cross-contamination

Introduction:During the COVID-19 pandemic, consideration was given to co-ventilating multiple patients on a single ventilator. Prior work had shown that this procedure was possible by ventilating four adult-size sheep for twenty-four hours, and other groups had performed this maneuver during dire circumstances. However, no investigation had examined the safety regarding cross-contamination. The purpose of our studies was to investigate if an infection could spread between individuals who were being co-ventilated.Method:Four sterile two-liter anesthesia bags were connected to a sterilized ventilator circuit to simulate the co-ventilated patients’ “lungs.” The circuit utilized Heat and Moisture Exchange filters and bacterial/viral filters, which were strategically inserted to prevent the transmission of infectious droplets. Serratia marcescens was inoculated into “lung” number one. The circuit was then run for 24 hours, after which each “lung” and three additional points in the circuit were cultured to see if S. marcescens had spread. These cultures were examined at 24 and 48 hours to assess for cross-contamination. This entire procedure was performed a total of four times.Results:S. marcescens was not identified in lungs two, three, or four or the three additional sampling sites on the expiratory limb of the tubing at 24 and 48 hours in all four trials.Conclusion:Cross-contamination between co-ventilated patients did not occur within 24 hours utilizing the described ventilator circuit configuration.

Uncovering the brain-wide pattern of synaptic input to vasopressin-expressing neurons in the paraventricular nucleus of the hypothalamus.

Arginine vasopressin (AVP) is a neuropeptide critical for the mammalian stress response and social behavior. AVP produced in the hypothalamus regulates water osmolality and vasoconstriction in the body, and in the brain, it regulates social behavior, aggression, and anxiety. However, the circuit mechanisms that link AVP to social behavior, homeostatic function, and disease are not well understood. This study investigates the circuit configurations of AVP-expressing neurons in the rodent hypothalamus and characterizes synaptic input from the entire brain. We targeted the paraventricular nucleus (PVN) using retrograde viral tracing techniques to identify direct afferent synaptic connections made onto AVP-expressing neurons. AVP neurons in the PVN display region-specific anatomical configurations that reflect their unique contributions to homeostatic function, motor behaviors, feeding, and affiliative behavior. The afferent connections identified were similar in both sexes and subsequent molecular investigation of these inputs shows that those local hypothalamic inputs are overwhelmingly nonpeptidergic cells indicating a potential interneuron nexus between hormone cell activation and broader cortical connection. This proposed work reveals new insights into the organization of social behavior circuits in the brain, and how neuropeptides act centrally to modulate social behaviors.

Automatized offline and online exploration to achieve a target dynamics in biohybrid neural circuits built with living and model neurons

Biohybrid circuits of interacting living and model neurons are an advantageous means to study neural dynamics and to assess the role of specific neuron and network properties in the nervous system. Hybrid networks are also a necessary step to build effective artificial intelligence and brain hybridization. In this work, we deal with the automatized online and offline adaptation, exploration and parameter mapping to achieve a target dynamics in hybrid circuits and, in particular, those that yield dynamical invariants between living and model neurons. We address dynamical invariants that form robust cycle-by-cycle relationships between the intervals that build neural sequences from such interaction. Our methodology first attains automated adaptation of model neurons to work in the same amplitude regime and time scale of living neurons. Then, we address the automatized exploration and mapping of the synapse parameter space that lead to a specific dynamical invariant target. Our approach uses multiple configurations and parallel computing from electrophysiological recordings of living neurons to build full mappings, and genetic algorithms to achieve an instance of the target dynamics for the hybrid circuit in a short time. We illustrate and validate such strategy in the context of the study of functional sequences in neural rhythms, which can be easily generalized for any variety of hybrid circuit configuration. This approach facilitates both the building of hybrid circuits and the accomplishment of their scientific goal.

Design of Monolithic RF CMOS Sub-mW Self-Oscillating-Mixers

In this paper, different topologies of RF self-oscillating mixers (SOM), stacking the voltage controlled oscillator (VCO) and the mixer on top of each other, are assessed. Their design considerations to address sub-mW operation suitable to ultra-low power applications are presented. Two configurations of SOM circuits are implemented in 130nm CMOS technology. The obtained results are presented and performances in terms of gain, noise, linearity, area, power consumption and stability over process and mismatch are compared and discussed.

Abstract LB161: Single cell bioprinted cell circuits for the systematic assessment of cell-cell communication in the early tumor microenvironment

Abstract The specific communication of multiple cell types in the tumor microenvironment plays a critical role in cancer progression. Current engineering methods have failed to adequately replicate the complexities of the tumor microenvironment (TME). In particular, generating engineered tissue-like environments with multiple TME cell types has remained challenging. Here we demonstrate the capability to pattern complex single cell circuit configurations, using a novel microfluidic bioprinting method, to study cell-cell communication in the early TME. A microfluidic dispenser (Biopixlar, Fluicell AB) was optimized to determine the delivery pressure (5 – 80 mbar), internal vacuum (0 – 80 -mbar), and external vacuum (0 – 80 -mbar) to enable highly controllable deposition of single cells suspended in complete media supplemented with polyethylene glycol (15 mg/mL, 1:1) at 1 × 106 cells/mL. Flow conditions were optimized for human cells: MDA-MB-231, MCF7, PC3, breast epithelial cells (MCF10a), fibroblasts, cancer associated fibroblasts, THP-1 derived macrophages, CD4+ T cells, CD8+ T cells, human umbilical vein endothelial cells (HUVECs), and mesenchymal stem cells. As proof of concept, the optimized settings were used to replicate a 2D tumor biopsy region of interest with high spatial precision. Next, cell-cell communication circuits were fabricated with cancer cells (PC3 or MDA-MB-231) and HUVECs. Communication circuits were bioprinted as 4 by 4 cell arrays, with 100 µm spacing between each cell, equal number of HUVECs and cancer cells, and three different cellular arrangements: alternating cell types, like cell types grouped, and groups of four like cell types. The circuits were live cell imaged for up to 30 hours to observe cell migration patterns, proliferation, and morphological changes as a function of cell-cell communication circuit arrangements. Optimal printing parameters were identified as 80 mbar delivery pressure, -25 mbar internal vacuum, and -55 mbar external vacuum. These parameters maintained >99% cell viability and ±10 µm spatial precision of printed cells. Live cell imaging of circuits containing PC3s or MDA-MB-231s with HUVECs on collagen substrates revealed changes in migration patterns, proliferation, and morphology depending on the surrounding cellular arrangement. HUVECs were highly migratory throughout the duration of the experiment, frequently extended protrusions towards nearby HUVECs, but did not display the same level of interaction with PC3s as they did with MDA-MB-231s. In MDA-MB-231 circuits, irrespective of patterning, we identified clear tendencies of HUVECs to herd MDA-MB-231s, travel overtop of MDA-MB-231s, collect and carry visible particles released from MDA-MB-231s, and maintain dendritic morphology instead of undergoing the expected vascular tubulogenesis. We found that HUVECs had the best morphology when clustered in groups of four and proliferated most when surrounded by MDA-MB-231s (alternating pattern). We found that MDA-MB-231s only proliferated when surrounded by HUVECs and had the least displacement when surrounded by like cells. These results demonstrate a method to precisely bioprint single cell circuits, enabling the investigation of cellular spatial organization and composition within the tumor microenvironment as it relates to tumor initiation and progression. Citation Format: Haylie R. Helms, Alexander E. Davies, Rebekka Duhen, Joshua M. Moreau, Ellen M. Langer, Luiz E. Bertassoni. Single cell bioprinted cell circuits for the systematic assessment of cell-cell communication in the early tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB161.

A Three-Phase Hybrid Multilevel Inverter With Enhanced Pulse-Width Modulation Strategy

This paper presents a three-phase hybrid multilevel inverter (MLI) with enhanced pulse-width modulation (PWM) strategy. The proposed hybrid MLI is developed based on the series connection of half-bridge and full-bridge for its level generation together with the T-type inverter for its polarity generation. The level and polarity generation circuits operate at high and fundamental frequencies respectively. An enhanced PWM strategy has been proposed to reduce the computational complexity and solve the high-frequency switching transitions issue in the existing hybrid MLI modulation method. The proposed MLI can produce 11 levels of line output voltage with reduced dc sources requirement. The detailed analyses which have been performed include the circuit configuration, operating principles and modeling, PWM signals generation, output voltage characteristics, dynamic response, harmonics content, power loss analysis and voltage stress of power switches. The results obtained from simulation and experiments verified the operating principle and functionality of the proposed hybrid MLI.

Development of a Bidirectional DC/DC Converter with Dual-Battery Energy Storage for a Hybrid Electric Vehicle System

Abstract: This study develops a newly designed, patented, bidirectional DC/DC converter (BDC) that interfaces a main energy storage (ES1), an auxiliary energy storage (ES2), and a DC-bus of different voltage levels, for application in hybrid electric vehicle systems. The proposed converter can operate in a step-up mode (i.e., low-voltage dual-source-powering mode) and a stepdown (i.e., high-voltage dc-link energy-regenerating mode), both with bidirectional power flow control. In addition, the model can independently control power flow between any two low-voltage sources (i.e., low-voltage dual-source buck/boost mode). Herein, the circuit configuration, operation, steady-state analysis, and closed-loop control of the proposed BDC are discussed according to its three modes of power transfer.

Three-dimensional inter-layer optical signal transmission realized by a monolithically integrated semiconductor-based carrier transport structure.

In this study, we proposed and demonstrated a brand new type of monolithic photonic devices which realizes the three-dimensional (3D) all-optical switching for inter-layer signal transmission. This device is composed of a vertical Si microrod which serves as optical absorption material within a SiN waveguide in one layer and as an index modulation structure within a SiN microdisk resonator lying in the other layer. The ambipolar photo-carrier transport property in the Si microrod was studied by measuring the resonant wavelength shifts under continuous-wave laser pumping. The ambipolar diffusion length can be extracted to be 0.88 µm. Based on the ambipolar photo-carrier transport in a Si microrod through different layers, we presented a fully-integrated all-optical switching operation using this Si microrod and a SiN microdisk with a pump-probe technique through the on-chip SiN waveguides. The switching time windows for the on-resonance operation mode and the off-resonance operation mode can be extracted to be 439 ps and 87 ps, respectively. This device shows potential applications for the future all-optical computing and communication with more practical and flexible configurations in monolithic 3D photonic integrated circuits (3D-PICs).

A Petri Net Model for Cognitive Radio Internet of Things Networks Exploiting GSM Bands

Quality of service (QoS) is a crucial requirement in distributed applications. Internet of Things architectures have become a widely used approach in many application domains, from Industry 4.0 to smart agriculture; thus, it is crucial to develop appropriate methodologies for managing QoS in such contexts. In an overcrowded spectrum scenario, cognitive radio technology could be an effective methodology for improving QoS requirements. In order to evaluate QoS in the context of a cognitive radio Internet of Things network, we propose a Petri net-based model that evaluates the cognitive radio environment and operates in a 200 kHz GSM/EDGE transponder band. The model is quite flexible as it considers several circuit and packet switching primary user network loads and configurations and several secondary user types of services (that involve semantic transparency or time transparency); furthermore, it is able to take into account mistakes of the spectrum sensing algorithm used by secondary users. Specifically, we derive the distribution of the response time perceived by the secondary users, where it is then possible to obtain an estimation of both the maximum throughput and jitter. The proposed cognitive radio scenario considers a secondary user synchronized access to the channel when using the GSM/EDGE frame structure.

Experimental investigation of a data-centre cooling system using a new single-phase immersion/liquid technique

This paper presents an experimental investigation conducted on a new single-phase immersion/liquid-cooling technique developed at the OVHcloud laboratory, combining a direct-to-chip water-cooling system with passive single-immersion cooling technology. The experimental setup tested the impact of three dielectric fluids (S5X, SmartCoolant and ThermaSafe R), the effect of the water circuit configuration, and the server power/profile. Results suggest that the system cooling demand depends on the fluid's viscosity. As the viscosity increased from 4.6 to 9.8 mPa s, the cooling performance decreased by approximately 6%. Moreover, all the IT server profiles were validated at various water inlet temperatures and flow rates. The energy performance of the proposed technique and the liquid-cooling system previously used by OVHcloud was compared at a 600 kW data centre (DC). The proposed technique showed a reduction in the DC electrical power consumption by at least 20.7% compared to the liquid-cooling system. Finally, the cooling performance of the air- and liquid-cooled systems and the proposed solution was compared computationally at the server level. When using the proposed solution, the energy consumed per server was reduced by at least 20% compared with the air-cooling system and 7% compared with liquid-cooling system.

Series-parallel mechanical circuit synthesis of a positive-real third-order admittance using at most six passive elements for inerter-based control

This paper investigates the circuit synthesis problem for a certain positive-real bicubic (third-order) admittance with a simple pole at the origin (s=0) to be realizable as a one-port series-parallel damper-spring-inerter circuit consisting of at most six elements, where the results can be directly applied to the design and physical realization of inerter-based control systems. Necessary and sufficient conditions for such a specific bicubic admittance to be realizable by a one-port passive series-parallel mechanical circuit containing at most six elements are derived, and a group of mechanical circuit configurations covering the whole set of realizability conditions are presented together with element value expressions. The conditions and element value expressions are related to the admittance coefficients and the roots of certain algebraic equations. The circuit synthesis results of this paper are illustrated by several numerical examples including the control system design of a train suspension system. Any realization circuit in this paper contains much fewer passive elements than the ten-element realization circuit by the well-known Bott-Duffin circuit synthesis approach. The investigations of this paper can contribute to the theory of circuit synthesis and many other related fields.

Novel cell balancing applied near-field coupling and Serial–Parallel Circuit configuration

This paper proposes a near-field cell balancing method to be applied to batteries of higher capacity and power. This method involves a wireless power transfer to balance battery cells, which produces higher efficiency than conventional passive approaches, and faster equalization than active approaches. Cell balancing is a crucial function of the battery management system (BMS) that maintains the balance of charge and discharge between cells of individual batteries. Furthermore, this method is designed to meet the increasing demand for faster cell balancing associated with high-capacity and high-power batteries. We selected a serial–parallel configuration to minimize the technical concern for isolation, or energy transfer to unselected cells. Experiments were conducted with two battery cells, and voltage equalization accelerated by 51% when the proposed cell balancing approach was applied.

Phase and Thermal-Driven Transport Across T-Shaped Double Quantum Dot Josephson Junction

The phase and thermal driven transport properties of the T-shaped uncorrelated double quantum dot Josephson junction are analyzed by using Keldysh non-equilibrium Green's function equation of motion technique. In this setup, we have shown that the side-attached quantum dot provides an additional route for electron transmission which is affecting the transport properties by adjusting the interdot hopping between the main dot and the side dot. We began with investigating the impact of interdot hopping on Andreev bound states and Josephson supercurrent. When a small thermal bias is applied across the superconducting leads, the system exhibits a finite thermal response which is primarily due to the, thermally induced, quasi-particle current. The behavior of the Josephson supercurrent and the quasi-particle current flowing through the quantum dots is examined for various interdot hopping and thermal biasing. Finally, the system is considered in an open circuit configuration where the thermally driven quasi-particle current is compensated by the phase-driven Josephson supercurrent and the thermophase effect is observed. The effect of interdot hopping and the position of quantum dot energy level on the thermophase Seebeck coefficient is investigated

Circuit Configuration and Operation Principle of Electrical Insulation Circuit for AC Fed Transformer-less Electric Vehicles Using High Withstand Voltage Property of SiC Power Module

This study aims to develop a power supply system without a traction transformer for weight reduction and downsizing. Transformer-less power supply is expected to realize step-down, rectification, isolation, and motor drive using a high voltage silicon carbide (SiC) power device. The primary challenge of this work is developing a novel circuit that isolates the motor drive circuit from the AC line without using the traction transformer. Accordingly, we devised a flying capacitor circuit to solve the existing problems and aims for capacitive isolation. Subsequently, we devise a nesting capacitor as a short-circuit prevention measure. We report the isolated circuit configuration and operating principle.

Comparison of ESD Damage Test for Common-Mode Chokes With ESD Gun and TLP-HMM

The method of electrostatic discharge (ESD) damage test for common-mode chokes has been standardized in IEC 62228–5 Annex E. However, there is a concern about the reproducibility of the ESD damage test using the ESD gun described therein. Against this background, the possibility of replacing the ESD gun with a transmission line pulse–human metal model (TLP-HMM) was investigated. The results of the ESD damage test using the ESD gun and TLP-HMM are found to be similar but not exactly the same, especially at low frequencies. Moreover, due to the different waveform generation principles and circuit configurations of the ESD gun and TLP-HMM, even if a load of the same structure is used to calibrate the ESD gun and TLP-HMM, when they are applied to other loads, it is still difficult to guarantee that the discharge currents are the same. The findings raise an issue on how to define a standard TLP-HMM so that it could provide the worst test result compared to the ESD gun.

Extracorporeal circulation models in small animals: beyond the limits of preclinical research.

Extracorporeal membrane oxygenation (ECMO) use has remarkably increased in recent years. Although ECMO has become essential for patients with refractory cardiac and respiratory failure, extracorporeal circulation (ECC) is associated with significant complications. Small-animal models of ECC have been developed and widely used to better understand ECC-induced pathophysiology. This review article summarizes the development of small-animal ECC models, including the animal species, circuit configuration, priming, perioperative procedures, cannulation, and future perspectives of small-animal ECMO models.

A Novel Non-Isolated High-Gain Non-Inverting Interleaved DC–DC Converter

High-gain DC-DC converters are being drastically utilized in renewable energy generation systems, such as photovoltaic (PV) and fuel cells (FC). Renewable energy sources (RES) persist with low-level output voltage; therefore, high-gain DC-DC converters are essentially integrated with RES for satisfactory performance. This paper proposes a non-isolated high-gain non-inverting interleaved DC-DC boost converter. The proposed DC-DC converter topology is comprised of two inductors and these are charging and discharging in series and parallel circuit configurations. The voltage multiplier technique is being utilized to produce high gain. The proposed topology is designed to operate in three modes of operation. Three switches are operated utilizing two distinct duty ratios to avoid the extreme duty ratio while having high voltage gain. Owing to its intelligent design, the voltage stress on the switches is also significantly reduced where the maximum stress is only 50% of the output voltage. The proposed converter's steady-state analysis with two distinct duty ratios is thoroughly explored. Furthermore, a 160 W 20/400 V prototype is developed for performance analysis and validation. The converter topology can generate output voltage with a very high voltage gain of 20, which is verified by the prototype. Moreover, a high efficiency of 93.2% is attained by the proposed converter's hardware prototype.

A Highly Efficient PFC Flyback Converter for Residential Lighting with Universal Input

This paper describes a power-factor-corrected-based flyback converter for low-power domestic lighting. The proposed flyback converter works in a discontinuous-conduction mode (DCM) and provides enhanced power-quality (PQ). In low-power residential lighting, the flyback converter is significantly preferred over non-isolated converters owing to its numerous advantages, such as its low component count, cost-effective solution, and safe operating conditions. The proposed DCM-based flyback converter has a simple circuit configuration and lower total harmonic distortions (THD) of input current by about 15% with an input power factor of around 0.97. A hardware prototype has been developed and examined at different AC source voltages to validate the feasibility and effectiveness of a proposed model. Experimental results show that the whole system efficiency satisfies Energy Star standards with 91.04 percent efficiency at a rated load of 24 Watts and 220 V AC mains and also fulfilled the stringent limits as per IEC61000-3-2 Class D standards.

Flexible and Low-Cost Emulation of Control Behaviors for Testing and Teaching of AC Microgrid

The fast development of distributed generations enables the microgrid a popular solution for the construction of the modern power grid, where the control behaviors of power electronics converters play a crucial role. Under this scenario, the emulation of microgrid control behaviors is becoming an emerging need for the testing and teaching of the AC microgrid. However, conventional approaches, such as the dynamic simulation test and the Power-Hardware-In-Loop, are still costly or bulky to flexibly recreate the correct characteristics of microgrid including different layers of controls and the interactions among multiple converters. The dynamic simulation test is bulky and costly to emulate various types of control behaviors since all physical components in the test system may need to be adjusted. The high cost of Power-Hardware-In-Loop is mainly caused by the high-performance real-time simulator and power amplifier. In this paper, a novel emulation system is proposed for the testing of the AC microgrid. A low-cost circuit configuration, which includes two face-to-face connected DC–AC converters and some passive loads, is introduced with the possibility of flexibly emulating most of the typical control schemes in an AC microgrid. In addition, a user interface for the real-time operation and measurement of the hardware platform is introduced on a host computer to further facilitate the testing process. Finally, various control schemes in microgrids, including the voltage control, current control, droop control, and secondary control, are validated in the experiment setup based on the proposed emulation approach.