Circuit Transmission Research Articles

Broadband Ultrasonic Array Transducer From Multilayer Piezoelectric Ceramic With Lowered Co-Firing Temperature.

Increasing array transducer bandwidth (BW) and signal-to-noise ratio (SNR) is a critical issue for producing a high-quality medical ultrasound image. However, array elements with small size tend to have poor sensitivity due to a much higher impedance compared with the electrical impedance of the transmitter and receiver circuit. Implementation of multilayer ceramic (MLC) is an effective way of reducing impedance, and thus, with a potential for improving SNR for an ultrasonic probe. In this work, we fabricated multilayer piezoelectric ceramic with a composition of 0.1Pb(Ni1/3Nb2/3)O3-0.35Pb(Zn1/3Nb2/3)O3-0.15Pb(Mg1/3Nb2/3)O3-0.1PbZrO3-0.3PbTiO3-4mol% excess NiO (PNN-PZN-PMN-PZ-PT), by a roll to roll tape casting process and co-fired with 90Ag/10Pd electrode at a low temperature of 950 °C. Using five-layer MLC (5L-MLC) as obtained, we designed and demonstrated a 5 MHz 32-element array transducer for ultrasonic and photoacoustic imaging. The five-layer transducer element exhibited a BW of 87% at -6 dB, substantially higher than 62% for single-layer ceramic (SLC) element. In addition, the insertion loss was improved by 16.2 dB over the SLC element with an external impedance of 50 Ω . Both the experimental results and theoretical analysis showed that our array transducer made of the PNN-PZN-PMN-PZ-PT MLC is promising for acquiring high-quality ultrasonic and photoacoustic images.

A Novel Physical Layer Authentication With PAPR Reduction Based on Channel and Hardware Frequency Responses

Next generation wireless communications such as 5G are expected to feature wide channel bandwidths on the order of hundreds of MHz. As bandwidths increase, circuit impairments caused by frequency dependent behaviour such as ripple and tilt in gain and group delay become more significant. PAPR of OFDM signals also increase with increasing number of sub-carriers. Transmitter circuit characterisation for the wide-band frequency response is needed to pre-compensate the signal to be transmitted. In this article, we propose a novel scheme which uses the circuit characteristics combined with the channel response to generate the keys for encrypting signals to provide an additional tier of security at the physical layer. The modulated constellation of the signal of interest is encrypted by dispersing its phases in addition to encrypting the bits using Diffie Hellman scheme. It is also shown that the method is able to reduce the PAPR of OFDM signals. This scheme is experimentally validated from end-to-end on a millimetre wave wireless link at 28.9 GHz demonstrating security against a well-positioned eavesdropper and a reduction of PAPR by 3.5 dB in a 2048 point OFDM signal with 1664 active QPSK modulated sub-carriers.

An Enhanced Fuzzy Rule Based Protection Scheme for TCSC Compensated Double Circuit Transmission System

ABSTRACT This paper introduces a fault detection and faulty phase selection technique for a double-circuit transmission line with thyristor-controlled series capacitor (TCSC). In a transmission system, the nonlinear operation of TCSC during switching modes distorted the voltage and current signals. The effect is more if the fault occurred at zero fault inception angle. An advanced protection approach to overcome these issues based on dynamic phasor estimation of current from local measurements is proposed in this work. The maximum transient component obtained from three phases is used as an index to accomplish the detection task. However, due to the nonlinear operation of different accessories connected to the controller unit such as metal oxide varistor (MOV) and thyristor circuit, identification of the exact faulty phase is still a challenge. To mitigate this issue, fuzzy decision-based rules are framed so that identification of exact faulty phases is possible. For validation, the method is tested on a 400-kV, 50-Hz power system model developed using EMTDC/PSCAD. Results obtained from simulation indicate that the method is reliable and a secure unit protection can be effectively provided to a double-circuit transmission system equipped with TCSC.

Design of Lithium Battery Equalization Circuit for Energy Multipath Transmission

Design of Lithium Battery Equalization Circuit for Energy Multipath Transmission

High-Speed Transmission Circuits Signaling in Optical Communication Systems

Abstract This paper has outlined high-speed transmission circuits signaling in guided or unguided optical communication systems. An efficient prediction scheme to predict the signal distortion caused by intersymbol interference. As high-speed digital signals exceed many gigabits per second speeds, eye diagrams provide the means to quickly and accurately measure signal quality and system performance. Semiconductor understands the capacitance constraints that designers are faced with when using these high-speed interfaces and offers a wide line of ultra-low capacitance electrical spectral density protection devices that service these interfaces, and the noise can be reduced at the optimum circuit at both bandwidths of 167 MHz, and bandwidth of 200 MHz.

Pain Inhibits GRPR Neurons via GABAergic Signaling in the Spinal Cord

It has been known that algogens and cooling could inhibit itch sensation; however, the underlying molecular and neural mechanisms remain poorly understood. Here, we show that the spinal neurons expressing gastrin releasing peptide receptor (GRPR) primarily comprise excitatory interneurons that receive direct and indirect inputs from C and Aδ fibers and form contacts with projection neurons expressing the neurokinin 1 receptor (NK1R). Importantly, we show that noxious or cooling agents inhibit the activity of GRPR neurons via GABAergic signaling. By contrast, capsaicin, which evokes a mix of itch and pain sensations, enhances both excitatory and inhibitory spontaneous synaptic transmission onto GRPR neurons. These data strengthen the role of GRPR neurons as a key circuit for itch transmission and illustrate a spinal mechanism whereby pain inhibits itch by suppressing the function of GRPR neurons.

Design of Lithium Battery Equalization Circuit for Energy Multipath Transmission

Design of Lithium Battery Equalization Circuit for Energy Multipath Transmission

Benefits of Sparse Tableau Over Nodal Admittance Formulation for Power-Flow Studies

Assembly of power-flow equations has traditionally begun from a nodal analysis formulation of the underlying transmission circuit's behavior. Most power-flow formulations encapsulate network constraints in the bus admittance matrix, $Y_{\text{bus}}$ . From a circuit perspective, this admittance representation restricts the network elements to be voltage controlled; resulting drawbacks treating zero-impedance branches in such applications as state estimation have long been recognized. This paper explores the advantages of the alternatives to $Y_{\text{bus}}$ -based formulations in power flow. It proposes a sparse tableau formulation (STF), and it demonstrates its computational efficiency, robustness, and generality in detailed comparison to traditional $Y_{\text{bus}}$ -based solution algorithms. In the examples of power networks ranging from 1888 to 82 000 buses, computational case studies indicate that STF provides comparable computational speed, while allowing simple treatment of zero-impedance branches and more reliably converging to solutions in many cases for which $Y_{\text{bus}}$ -based Newton algorithms diverge.

Development of low inductance circuit for radially symmetric circuit

The switch of the radially-symmetric circuit using semiconductors of SiC-MOSFET, which is one of the next-generation semiconductors, consists of a circuit in which many semiconductor switches are arrayed in parallel. Since all parallel circuits are equal in length, distortion due to timing jitter or impedance difference does not occur on principle in the merged output waveform. This circuit is useful for outputting an ultrashort pulse waveform. Therefore, we have developed a circuit board that achieves even lower inductance of the power transmission circuit by making a double ring structure equivalent to a coaxial shape. We compare the results of calculation, analysis and measurement, and the superiority of the developed coaxial-type is presented here.

"Return to the Soil" Nanopaper Sensor Device for Hyperdense Sensor Networks.

A nanopaper sensor device that combines humidity sensing, wireless information transmission, and degradability has been fabricated using wood-derived nanopaper as the substrate and dielectric layers. The nanopaper shows excellent suitability for capacitor dielectric layers because of its high dielectric constant, insulating properties suitable for thin-film formation, and lamination properties. A wireless transmission circuit containing the nanopaper capacitor can transmit radio signals in the megahertz band, and the relative humidity change can be output as a change in the radio signal owing to the humidity sensitivity of the nanopaper capacitor. More than 95% of the total volume of the nanopaper sensor device decomposes in soil after 40 days. Because the nanopaper sensor device does not need to be recovered, it is expected to greatly contribute to a sustainable society through realization of hyperdense observation networks by mass installation of sensor devices.

Nd$_{{x}}$ Fe$_{1-{x}}$ N$_{{y}}$ Magnetic Core Application for Resonance Coil of 13.56 MHz GaN Wireless Power Transmission

In this study, the Nd x Fe1− x N y materials are applied for the magnetic core of the series resonance circuit of GaN wireless power transmission (WPT) for the first time. At over 10 MHz, the inductance of the fabricated Nd2Fe17N3 coil is stable at $1.15~\mu \text{H}$ and the effective magnetic permeability of the Nd2Fe17N3 is estimated to be 2.6. At the same inductance, the number of turns of the Nd2Fe17N3 coil can be decreased as compared with that of the air-core coil, and the coil size can be reduced by 0.7 times by using the Nd2Fe17N3 material. At the 13.56 MHz GaN-WPT operation, the successful WPT waveforms can be obtained, and the drastic reduction of the energy loss at the coil is achieved due to the low imaginary part of the magnetic permeability. The Nd-Fe-N materials are considered indispensable to GaN high-frequency switching circuits.

The Possible Mechanism of the Appearance of Nightmares in Post-Traumatic Stress Disorder and Approaches to Their Prevention

Abstract—It is hypothesized that the basis of nightmares in post-traumatic stress disorder (PTSD) is modification of synaptic transmission in neural circuits that contain one of the following structures: the visual cortex, prefrontal cortex (PfC), basolateral amygdala (BLA), hippocampus, connected with them nuclei of the thalamus and basal ganglia (BG). The emergence of dreams is promoted by the induction of long-term potentiation of excitatory inputs to the striatonigral cells and the long-term depression of the inputs to the striatopallidal cells that are connected with the visual cortex, and give rise, respectively, to a direct and indirect path way through the BG. This leads to synergistic disinhibition of certain groups of neurons in the thalamus by the output BG nuclei and the formation of activity patterns that reflect dream content in the areas of the visual cortex and hippocampus, which are connected with thalamus. The occurrence of emotionally negative episodes in dreams is a consequence of an increase in BLA activity during PTSD, whose signals are summed with the signals from the hippocampus and PfC on the neurons of the ventral striatum. This mechanism suggests that, in order to prevent nightmares, it is necessary to induce long-term depression of the excitatory inputs to the neurons of the limbic structures and to the striatonigral cells. It is undesirable to act on the receptors on the striatopallidal cells because it may simultaneously induce long-term potentiation of the excitatory inputs to the neurons of PfC, BLA, and hippocampus, which have receptors of the same types. Given the data on the types of receptors on striatal neurons, it follows from the modulation rules we earlier formulated that nightmares may be prevented by antagonists of dopamine D1 receptor and alpha1 adrenoceptor and agonists of glucocorticoid, serotonin 5-HT1B, and cannabinoid CB1 receptors. The use of mineralocorticoid and serotonin 5-HT2A receptor agonists, as well as antagonists of alpha2 adrenoreceptors and dopamine D2 receptors (which are part of some antidepressants and antipsychotics) is undesirable in order to avoid side effects. The treatment should be short-term and used only at bedtime, to avoid impairments of physical activity and sensory perception in the awake state. The consequences of the proposed mechanism are consistent with the known results of clinical studies.

Wireless power transfer using the concept of magnetic coil resonant system

Long life lithium ion batteries and methanol fuel cells have been persuaded as ways to make the electrical components more mobile, consumers expectations are still far from being met due to the added weight and expenses for battery replacement. The discovery of wireless power transfer as a new option, and holds great promise to leave the oversized battery. The design of wireless power transfer applies the concept of Magnetic Coil Resonant System (MCRS). The concept of MCRS is similar with a function of an antenna to transfer the power from one point to another. Multisim13.0 software is applied to predict the performance of the proposed MCRS. This software simulation is useful to estimate the output wave on the virtual oscilloscope and to obtain the reading of output voltage from the virtual multimeter. The transmitter side contains power supply, transmitter oscillator circuit and transmitter magnetic coil. Transmitter circuit convert DC to AC waveform and the receiver circuit convert AC to DC voltage. The DC Source that connected to Transmitter was provided by the DC source regulator acts as DC source to adjust Voltage and Current separately. The project show the efficiency of the wireless power transfer with different coil diameter and a distance between the transmitter and receiver coil. At a distance of 15 cm, power are successfully transmitted as it is indicated by the LED light to turn on. The increment of size in coil diameter has given a higher power and longer coverage distance for wireless transfer power.

In‐line ports feeding substrate integrated waveguide resonator with higher order modes suppression

In-line ports are usually used to feed substrate integrated waveguide (SIW) resonator in an in-line transmission circuit. However, the higher order mode TE 102 is excited as well as the fundamental mode TE 101 thereby deteriorating the selectivity. Here the authors present a method to remove the selectivity deterioration. By additionally introducing TE 201 , the TE 102 and the TE 201 can be counteracted with each other by taking advantage of their out-phase out-coupling, and then both modes are suppressed well in a SIW resonator feeding with in-line ports. Two prototypes based on square and rectangle cavity are fabricated, respectively and measured to verify the proposed technique. The results agree with the expectation well. It shows the potential to be implemented in the in-line transmission circuit with SIW resonator.

A parametric simulation of the wireless power transfer with inductive coupling for electric vehicles, and modelling with artificial bee colony algorithm

In recent years, electrical power transmission has been intensified by the use of wireless power transfer (WPT). In this study, a new mathematical expression that calculates the efficiency of the charging process for a single phase coreless transformer and the inductive power transmission circuit that can be used in the wireless charging station of electric vehicles was proposed. An experimental design was performed by using central composite design and ranges of a few parameters selected for the transformer and power transmission circuit for 540 simulations. The expression that calculates the charging efficiency was obtained by using the artificial bee colony algorithm. An expression that consists of optimization variables and efficiency parameters and also conforms to simulation data was obtained. The variables of expression in the optimization process were determined optimally by harmonizing of the simulation results and the outputs of expression produced by using the artificial bee colony algorithm. The results show that the analyzes of the WPT circuits related to the charging efficiency can be easily calculated with the proposed expression without considering simulation, measurement and sophisticated mathematics.

Traveling Waves-Based Method for Fault Estimation in HVDC Transmission System

The HVDC transmission system is winning hearts of researchers and electrical engineers because of its notable merits as compared to the HVAC transmission system in the case of long-distance bulk power transmission. The HVDC transmission system is known for its low losses, effective control ability, efficiency and reliability. However, because of the sudden build-up of fault current in the HVDC transmission system, conventional relays and circuit breakers are required to be modified. Detection of fault location is an important parameter of protection of the HVDC transmission system. In this research paper, fault location methods based on traveling waves are reviewed for the HVDC transmission system. Arrival time and natural frequency are the two parameters of measurement in traveling waves. Advantages and disadvantages of methods of traveling waves with respect to their quantities of measurements are analyzed critically. Further, a two-terminal HVDC test grid is simulated over Matlab/Simulink. Different types of AC and DC faults and at different locations are analyzed on a test grid. A traveling wave-based technique of fault estimation is developed and is evaluated for identification, classification and finding location of faults to validate its performance. Moreover, this technique is supported with analysis of fast Fourier transform to accelerate its practicality and realization.

Passive Wireless Measurement System Based on Wireless Power Transfer Technology

This paper presents a passive wireless measurement system based on wireless power transfer (WPT) technology. It does not require separate information and power transmission circuits. The data receiver only needs to send a short signal to the data collector through WPT, and then the information of the measured environment can be obtained by analyzing the feedback signal from the data collector. Three concepts are included in this system, namely (1) the constant oscillation period of oscillation attenuation waveforms; (2) the characteristics of inductive coupling WPT; and (3) the relationship between sensitive resistances and environmental parameters. It is very suitable for measuring the parameters in an internal or closed space. The data collector is small in size and simple in structure, and no power is needed. It has stable performance after implantation and can be used permanently. Results obtained from simulations and experiments are included. They verify the measurement process and measurement results meet the requirements of passive wireless measurement, and the measurement error is less than 1.5%.

Preliminary design and characterization of a low-cost and low-power visible light positioning system.

Designs and results for a low-power and economical fingerprint visible light positioning (VLP) system are discussed in this paper. A system using four white LEDs and one photodiode was deployed. The LEDs are independently controlled and modulated by individual transmitter circuits, removing the requirement for a large, expensive signal generator. The receiver circuit filters and converts the received signal to DC, allowing a simple microcontroller to save the received signal. We propose the creation of a fingerprint database by recording signal data, fitting a two-dimensional Gaussian distribution to the data, and then generating the fingerprint database for all positions in the evaluation system. System positioning accuracy of 13.44+/-0.36 mm was observed, corresponding to a relative error of 2.8% with respect to the system dimensions. This result presents an improvement on positioning accuracy for fingerprint positioning VLP systems, which build their own transmitters.

An Accurate and Compact High Power Monocycle Pulse Transmitter for Microwave Ultra-Wideband Radar Sensors with an enhanced SRD model: Applications for Distance Measurement for lossy materials

In This paper, a high power sub-nanosecond pulse transmitter for Ultra-wideband radar sensor is presented. The backbone of the generator is considered as a step recovery diode and unique pulse injected into the circuit, which gives rise to an ultra-wide band Gaussian pulse. The transistor driver and transmission line pulse forming the whole network are investigated in detail. The main purpose of this work is to transform a square waveform signal to a driving pulse with the timing and the amplitude parameters required by the SRD to form an output Gaussian pulse, and then into high monocycle pulses. In simulation aspect, an improved output response is required, in this way a new model of step recovery diode has been proposed as a sharpener circuit. This proposition was applied to increase the rise-time of the pulses. For a good range radar, a high amplitude pulse is indispensable, especially when it comes to penetrate thick lossy materiel. In order to overcome this challenge, a simple technique and useful solution is introduced to increase the output amplitude of the transmitter. This technique consists to connect the outputs of two identical pulse generators in parallel respecting the restrictions required. The pulse transmitter circuit is completely fabricated using micro-strip structure technology characteristics. Waveforms of the generated monocycle pulses over 10V in amplitude with 3.5 % in overshoot have been obtained. Good agreement has been achieved between measurement and simulation results.

Design and Development of an Inexpensive Sub-Nanosecond Gaussian Pulse Transmitter

A design of a hybrid Gaussian pulse transmitter using a transistor-based pulse generator and two pulse-shaping networks, a shorted stub delay circuit and a 90° hybrid coupler, is presented. A transistor-based pulse generator drives the pulse-forming network to achieve a sub-nanosecond pulsewidth. The shorted stub delay line was modified to optimize the frequency response and phase linearity. The transistor-based pulse generator is an inexpensive way of producing a square pulse of sharp rise time; this design achieved 280-ps rise time. A Schottky diode was used to eliminate the negative part of the output pulse as well as to reduce the ringing. Multiple simulations and measurements were performed to study the circuit behavior. The measurement results demonstrated a pulsewidth as sharp as 153 ps with 0.83-V amplitude and a low ringing on the order of 10%. The Gaussian monopulse was obtained by feeding the Gaussian pulse to a broadband 90° hybrid, which acts as a differentiator in the time domain. The pulse has a width on the order of 100 ps. The transmitter circuit was completed by connecting the monopulse circuit with an antenna. The measured radiated pulse in the far field of the transmitter is a second derivative Gaussian pulse with 85 ps of pulsewidth.