Circuit Transmission Research Articles

Extreme Speed Power-DAC: Leveraging InP DHBT for Ultimate Capacity Single-Carrier Optical Transmissions

Power-digital-to-analog converters (DAC) circuits for high capacity and high spectral efficiency optical transmitters are presented in this paper. They are based on a 0.7- μ m InP DHBT semiconductor process, of which main differentiating characteristics are highlighted. We introduce the Power-DAC circuit concept, its usual architectures, and we provide design details of its latest generation. Named SPDAC, it integrates multiplexing front-end blocks composed of three 2:1-selectors. With this architecture, the input interface operates at half rate. 107-GBd operation for PAM-4 and 64-GBd for PAM-8 were demonstrated with quality suitable for direct detection and datacenter applications. 90-GBd operation in a PDM-64QAM transmitter with coherent detection was also enabled by SPDAC modules. With 3.7 to 4 V differential output voltage swing, Power-DAC circuits can be directly connected to different types of E/O modulators (Mach–Zehnder, EAM). We show in particular how the SPDAC circuit enables single-carrier transmission at 100-GBd in PAM-4 IM/DD modulation for datacenters. In this experiment, the feed-forward equalizer combined with stacking a <3-symbol memory sequence estimator demonstrated signal recovery for 107-GBd PAM-4 in back-to-back configuration, after 500 m and 1 km of transmission over standard single-mode fiber for 100- and 84-GBd PAM-4 configuration, respectively.

A New Type of Self Driven Door Handle

In this article, authors report on a smart door handle that can efficiently collect and utilize ambient energy to power itself. A Triboelectric Nanogenerator which presents characteristics including easy fabrication, small size and light weight is embedded in the door. When begin to turn the handle, the TENG can convert the mechanical energy into the electrical energy, and the power can up to 0.023W. At the same time, the internal circuit will send a single to identify the action of opening the door, and then the wireless receiver will make appropriate responses after receiving the signal. In this article, the authors designed a wireless transmission circuit to ensure that the transmitter and receiver can communicate in real time. Due to the TENG's output is AC signal which can't power the device directly, so the power management circuit was designed to process the signal. To analyze and compare the output signal, the authors designed two power management circuits. Both the circuits can convert the AC signal into the DC signal, the voltage can up to 5V and the current can up to 3mA.

Conformation-based signal transfer and processing at the single-molecule level.

Building electronic components made of individual molecules is a promising strategy for the miniaturization and integration of electronic devices. However, the practical realization of molecular devices and circuits for signal transmission and processing at room temperature has proven challenging. Here, we present room-temperature intermolecular signal transfer and processing using SnCl2Pc molecules on a Cu(100) surface. The in-plane orientations of the molecules are effectively coupled via intermolecular interaction and serve as the information carrier. In the coupled molecular arrays, the signal can be transferred from one molecule to another in the in-plane direction along predesigned routes and processed to realize logical operations. These phenomena enable the use of molecules displaying intrinsic bistable states as complex molecular devices and circuits with novel functions.

Transparent and Flexible Triboelectric Sensing Array for Touch Security Applications.

Tactile sensors with large-scale array and high sensitivity is essential for human-machine interaction, smart wearable devices, and mobile networks. Here, a transparent and flexible triboelectric sensing array (TSA) with fingertip-sized pixels is demonstrated by integrating ITO electrodes, FEP film, and signal transmission circuits on an undivided palm-sized polyethylene terephthalate substrate. The sensing pixels can be triggered by the corresponding external contact to induce the electrostatic potential in the transparent electrodes without power consumption, which is individually recognized by the sensor. By testing the response of the pixels, the electrical characterization is systematically investigated. The proposed TSA exhibits excellent durability, independence, and synchronicity, which is able to realize real-time touch sensing, spatial mapping, and motion monitoring. The integrated TSA has great potential for an active tactile system, human-machine interface, wearable electronics, private communication, and advanced security identification.

Low power wide spectrum optical transmitter using avalanche mode LEDs in SOI CMOS technology.

This paper presents a low power monolithically integrated optical transmitter with avalanche mode light emitting diodes in a 140 nm silicon-on-insulator CMOS technology. Avalanche mode LEDs in silicon exhibit wide-spectrum electroluminescence (400 nm < λ < 850 nm), which has a significant overlap with the responsivity of silicon photodiodes. This enables monolithic CMOS integration of optocouplers, for e.g. smart power applications requiring high data rate communication with a large galvanic isolation. To ensure a certain minimum number of photons per data pulse (or per bit), light emitting diode drivers must be robust against process, operating conditions and temperature variations of the light emitting diode. Combined with the avalanche mode light emitting diode's steep current-voltage curve at relatively high breakdown voltages, this conventionally results in high power consumption and significant heating. The presented transmitter circuit is intrinsically robust against these issues, thereby enabling low power operation.

Bidirectional Current-Fed Half-Bridge (C) (LC)–(LC ) Configuration for Inductive Wireless Power Transfer System

This paper contributes to the analysis and development of a new power electronics system for bidirectional wireless power transfer (WPT). The major focus is the analysis and implementation of a new current-fed resonant topology with current-sharing and voltage-doubling features. A new bidirectional WPT system with current-fed half-bridge voltage-doubler circuit is proposed and analyzed with series–parallel and series resonant networks. Traditionally used parallel L–C resonant tank in transmitter circuit with current-fed WPT topology causes higher voltage stress across the inverter devices to compensate the reactive power consumed by the loosely coupled coil. In the proposed topology, this is mitigated by adding a suitably designed capacitor in series with the transmitter coil; thus, developing a series–parallel CLC tank. Detailed analysis and design is reported for both grid-to-vehicle and vehicle-to-grid operations. The power flow is controlled through variable frequency modulation. Soft switching of the devices is obtained irrespective of the load current. A proof-of-concept experimental hardware prototype rated at 1.2 kW is developed and tested. Experimental results are presented to verify the analysis and demonstrate the performance of the system with bidirectional power flow.

Floating Monopole Antenna on a Tethered Subsurface Sensor at 433 MHz for Ocean Monitoring Applications

Low-cost tethered buoys are important for seawater observation, coastal area monitoring, and pollution sensing. Underwater sensor networks operating at 433 MHz (ISM band) suffer high attenuation due to seawater conductivity. Significant propagation distance cannot be achieved through seawater or along the seabed. This paper reports a novel technique for communication between sensors operating in shallow water. A sensor tethered to the bottom was connected to a floating monopole antenna via an insulated wire transmission line. Experiments and calculations show that the attenuation along the transmission line was 38 dB/m. Surface propagation for buoy-to-base station was approximately 1 dB/m with a communication range of 30 m using a 10-dBm transmitter circuit with receiver sensitivity of ${-}$ 110 dBm. For buoy to buoy the surface propagation was measured as 3.5 dB/m with a communication range of 4 m. Experiments were carried out in calm water conditions. The results demonstrate that significant sensor network coverage of coastal regions is possible.

Design of full-duplex and multifunction bidirectional CMOS transceiver for optical interconnect applications

This work presents a full-duplex and multifunction bidirectional transceiver for optical interconnect application. The transceiver utilizes a common limiting amplifier/gain stage, thus reducing total chip area and total power consumption. While providing a full-duplex bidirectional transmission with the aid of a hybrid circuit between the electrical input/output (I/O) and the optoelectronic signals from the transmitter and receiver circuits, it also allows for a half-duplex operation with the aid of a switch between the transimpedance amplifier signals and the transmitter electrical input from the I/O port. The multifunction bidirectional CMOS transceiver is designed in a 0.13 µm Si-CMOS technology, with power dissipation of 79 and 54.4 mW for the transmitter and receiver, respectively. It shows a 3-dB bandwidth of 5.58 and 5.69 GHz for the transmitter and the receiver respectively and with a 3-dB gain of 66.14 and 69.6 dB, in full-duplex mode. The transceiver operates up to 7 Gb/s in full-duplex mode.

The Study on Resonant Multi-Frequency Array Electrical Logging System

Multi-frequency array induction logging method using a combination of high and low frequency can keep both vertical stratification and probing depth capabilities of logging instrument, and in order to reach a certain field strength in strata, the transmission circuit need provide greater current to the transmitter coil system. This paper studied resonant multi-frequency electrical logging system using resonant transmission mode, it mainly researched multi-frequency, high-frequency signal generator unit, power amplifier unit and analysed induced electromotive force calculation method of receiving coil. Combining the transmission and reception experiment, parameters such as the emission current and induced electromotive force of receiving coil have been achieved, those can verify theoretical derivation. The paper provides good design method of excitation source and analysis of receiving characteristics, at the meanwhile, it can play an important role in development and application of multi-frequency array electrical logging methods.

A novel tri-band T-junction impedance-transforming power divider with independent power division ratios.

In this paper, a novel L network (LN) is presented, which is composed of a frequency-selected section (FSS) and a middle stub (MS). Based on the proposed LN, a tri-band T-junction power divider (TTPD) with impedance transformation and independent power division ratios is designed. Moreover, the closed-form design theory of the TTPD is derived based on the transmission line theory and circuit theory. Finally, a microstrip prototype of the TTPD is simulated, fabricated, and measured. The design is for three arbitrarily chosen frequencies, 1 GHz, 1.6 GHz, and 2.35 GHz with the independent power division ratios of 0.5, 0.7, and 0.9. The measured results show that the fabricated prototype is consistent with the simulation, which demonstrates the effectiveness of this proposed design.

Simultaneous wireless power transfer and data communication using synchronous pulse-controlled load modulation

Wireless Power Transfer (WPT) and wireless data communication are both important problems of research with various applications, especially in medicine. However, these two problems are usually studied separately. In this work, we present a joint study of both problems. Most medical electronic devices, such as smart implants, must have both a power supply to allow continuous operation and a communication link to pass information. Traditionally, separate wireless channels for power transfer and communication are utilized, which complicate the system structure, increase power consumption and make device miniaturization difficult. A more effective approach is to use a single wireless link with both functions of delivering power and passing information. We present a design of such a wireless link in which power and data travel in opposite directions. In order to aggressively miniaturize the implant and reduce power consumption, we eliminate the traditional multi-bit Analog-to-Digital Converter (ADC), digital memory and data transmission circuits all together. Instead, we use a pulse stream, which is obtained from the original biological signal, by a sigma-delta converter and an edge detector, to alter the load properties of the WPT channel. The resulting WPT signal is synchronized with the load changes therefore requiring no memory elements to record inter-pulse intervals. We take advantage of the high sensitivity of the resonant WPT to the load change, and the system dynamic response is used to transfer each pulse. The transient time of the WPT system is analyzed using the coupling mode theory (CMT). Our experimental results show that the memoryless approach works well for both power delivery and data transmission, providing a new wireless platform for the design of future miniaturized medical implants.

Immunized-Evolutionary Algorithm Based Technique for Loss Control in Transmission System with Multi-Load Increment

&lt;div&gt;&lt;p&gt;Loss issue is significant in power system since it affects the operation of power system, which ultimately can be translated to monetary effect. Incremental demand that explicitly adding the reactive load causes extra heating losses in the transmission circuit. Without appropriate remedial control, the temperature increase on transmission line cable would end with insulation failure. This phenomenon can be alleviated with a proper compensation scheme that provides optimal solution along with avoidance of under-compensation or over-compensation. Evolutionary Programming (EP) has been recognised as one of the powerful optimisation technique, applied in solving power system problems. Nevertheless, EP is an old technique that sometimes could reach to a settlement that is not fully satisfied. Thus, the need for a new approach to improve the setback is urgent. This paper presents immunized-evolutionary algorithm based technique for loss control in transmission system with multi-load increment. The classical EP was integrated with immune algorithm so as to reduce the computational burden experienced by the classical EP.&lt;strong&gt; &lt;/strong&gt;The algorithm has been tested on a IEEE 12-Bus System and IEEE 14-Bus System.&lt;strong&gt; &lt;/strong&gt;Comparative study was conducted between EP and IEP in terms of optimisation performance. The optimal size and location of PV determined by IEP was able to control the loss in transmission system when the load increases. Results obtained from the studies revealed the merit of the proposed IEP; indicating its feasibility for future implementation in practical system.&lt;/p&gt;&lt;/div&gt;

Ultra-Low-Loss High-Contrast Gratings Based Spoof Surface Plasmonic Waveguide

Large metallic losses and short propagation lengths associated with surface plasmons (SPs) have long been considered as the obstacles which severely limit the practical applications of surface plasmonic waveguides. In this paper, we introduce the concept of dielectric spoof SPs (SSPs) and show that subwavelength high-contrast gratings (HCGs) offer a route to effectively suppress the losses and hence dramatically increase the propagation length of surface electromagnetic waves. We experimentally realized a wideband ultra-low-loss high-confinement plasmonic waveguide constructed by a high refractive-index dielectric array with deep-subwavelength periodicity on a metal substrate. Simulation and measurement results on the near-field distributions and S-parameters at microwave frequencies provide explicit evidences of strong field localization and show excellent transmission efficiency of HCGs-based SSPs across a broad frequency band. More importantly, the propagation length of the HCGs-based SSPs is proved to be at least more than one order of magnitude larger than that of metallic gratings-based SSPs at the same or even higher level of field confinement. Thus, the SSPs as experimentally realized in this paper hold great promise for numerous practical applications in ultra-low-loss and long-range transmission SP devices and circuits and may open up new vistas in SP optics.

InP HBT Technologies for THz Integrated Circuits

Highly scaled indium phosphide (InP) heterojunction bipolar transistor (HBT) technologies have been demonstrated with maximum frequencies of oscillation ( $f_{\max}$ ) of >1 THz and circuit operation has been extended into the lower end of the terahertz (THz) frequency band. InP HBTs offer high radio-frequency (RF) output power density, millivolt (mV) threshold uniformity, and high levels of integration. Integration with multilevel thin-film wiring permits the realization of compact and complex THz monolithic integrated circuits (TMICs). Circuit results reported from InP HBT technologies include: 200-mW power amplifiers at 210 GHz, 670-GHz amplifiers and fundamental oscillators, and fully integrated 600-GHz transmitter circuits. We review the state of the art in THz-capable InP HBT devices and integrated circuit (IC) technologies. Challenges in extending transistor bandwidth and in circuit design at THz frequencies will also be addressed.

Energy Efficiency Improvement of Coded OFDM Systems Based on PAPR Reduction

For long-distance wireless communications, a power amplifier (PA) is one of the most power-hungry devices at a transmitter. In many recent wireless standards that pursue higher spectral efficiency, signaling techniques with a high peak-to-average power ratio (PAPR) such as orthogonal frequency-division multiplexing (OFDM) have been adopted, but they typically end up with poor PA efficiency. A variety of PAPR reduction approaches have been thus proposed in literature to improve the power efficiency from the physical-layer perspective. In this paper, we investigate how much improvement in terms of the power efficiency can be achieved by such PAPR reduction techniques for OFDM signaling, and we evaluate the achievable coded frame error rate (FER) from a viewpoint of system-level design. It reveals that, in addition to the improvement of the PA efficiency, carefully designed PAPR reduction techniques in fact have a potential of reducing the required signal-to-noise power ratio at a receiver for achieving a given target FER and reducing the duty cycle of a transmitter circuit for a given target information rate. This in turn helps in reducing the total energy consumed at the transmitter of mobile terminals and thus leads to greener communication systems.

A general design of magnetic coupling resonant wireless power transmission circuit

As a new kind of power transmission way, wireless power transmission technology has great advantages compared with traditional power transmission way.This paper introduces the basic structure and working principle of magnetic coupling resonant wireless power transmission. Based on this, main circuit design and analysis of the transmission system is given. What’s more, about the future research work is its functional operation accomplishment.

Developmental regulation of SMN expression: pathophysiological implications and perspectives for therapy development in spinal muscular atrophy.

Spinal muscular atrophy (SMA), the predominant form of motoneuron disease in children and young adults is caused by loss of function of the SMN protein. On the basis of a disrupted splice acceptor site in exon 7, transcripts from a second SMN gene in humans called SMN2 cannot give rise to SMN protein at sufficient levels for maintaining function of motoneurons and motor circuits. First clinical trials with Spinraza/Nusinersen, a drug that counteracts disrupted splicing of SMN2 transcripts, have shown that elevating SMN levels can successfully interfere with motoneuron dysfunction. This review summarizes current knowledge about the pathophysiological alterations in Smn-deficient motoneurons, which lead to defective neuromuscular transmission and altered spinal circuit formation. Both pathological mechanisms are important targets for therapeutic intervention. However, the developmental time window when therapeutic interventions ideally should start is not known. Endogenous SMN expression both from SMN1 and SMN2 genes is high at early developmental stages and declines progressively in humans and mice. Thus, therapeutic SMN upregulation should start just before SMN declines below a critical threshold, and before irreversible defects occur at neuromuscular junctions and in spinal circuits. Previous results indicate that loss of Smn function leads to synaptic dysfunction during a stage of neuromuscular development when synaptic strength determines which synapses are maintained or not. This time window appears as an important target for therapy, which possibly could be supported by additional strategies that strengthen synaptic transmission.

Anemometric type flow transmitter using LM335 – A temperature sensing IC

In the present paper, an adapted anemometric type flow measurement technique has been designed and developed. To measure the flow rate of the fluid, a temperature sensing IC LM335 has been used in this technique as a flow sensor. The flow sensing IC is used to produce a change in output voltage of the flow transducer due to cooling effect of a flowing fluid on the metal cap of the IC sensor in contact with the fluid. In this transducer, the effect of fluid temperature is eliminated by using an identical IC sensor with its metal cap in contact with a stagnant part of the flowing fluid. Thus the difference of the outputs of the two identical transducers gives an output which depends only on fluid flow rate. The transducer along with signal conditioner and transmitter is designed and tested in the present work. The test results are reported in the paper. A characteristic equation of the proposed flow transducer has been derived and transducer characteristics obtained from experiment are found to follow this equation with good linearity, repeatability and small uncertainty of measurement. The signal conditioner and transmitter circuits used in this experiment are also found to have similar characteristics.

High Performance, Biodegradable Electrochemical Capacitors for Transient Electronics

Various electronic devices with high performance and advanced structures have been effectively integrated into a functional electronic system owing to their miniaturization. In particular, extensive research on miniaturized devices that gradually lose their functionality by dissolution in water/biofluid has been recently conducted, which would accelerate the development of eco-friendly as well as bio-implantable devices for transient electronics. To satisfy the technological demand for continuous powering of implanted devices in the human body regardless of the time and place, the development of high performance wireless power generation and energy storage devices is required. Supercapacitors, so-called next-generation energy storage devices, can be used in the event of unexpected power-off owing to their superior power density and long cycling lifetimes compared to batteries. Therefore, the application of transient supercapacitors as devices essential to integrated electronic circuits in the human body is expected to play an important role in the advancement of independent and sustainable transient electronics. Here, we introduce the fabrication and applications of fully biodegradable microsupercapacitors (MSCs) consisting of interdigitated water-soluble metal (W, Fe, and Mo) electrodes, a hydrogel electrolyte (agarose gel), and a biodegradable poly(lactic-co-glycolic acid) (PLGA) substrate, encapsulated with thin films of PLGA and polyanhydride. In particular, this unusual energy storage device based on 300 nm thick Mo electrode exhibits electrochemical performance with a areal capacitance of 1.6 mF/cm2, energy density of 0.14 µWh/cm2, and power density of 1.0 mW/cm2. Such high performance is attributed to the pseudocapacitance originating from the metal-oxide film generated by electrochemical corrosion at the interface between the metal electrode and the water-containing agarose gel electrolyte, during repeated charge/discharge cycles. The oxidation states of those oxide layers are confirmed to be WO3, Fe2O3, and MoO3, respectively, via taking scanning electron microscope images and x-ray photoelectron spectra. The dissolution kinetics of all components of the MSCs are measured in phosphate-buffered saline at body temperature and an encapsulation strategy is suggested to control the functional lifetimes of the MSCs. Finally, we demonstrate the potential applications of the fabricated biodegradable MSCs as transient energy storage devices by illuminating a light-emitting diode and as a transient capacitor in integrated circuits for wireless power transmission.

Experience of Severe Overvoltage in an Interconnected Transmission Subnetwork During Single-Phase Open Period

A single-phase trip and reclose scheme applied to a long transmission circuit, interconnecting a remote subnetwork to the grid, improves the interconnection reliability. However, the entire subnetwork loses supply in one phase should there be no generation connected in it during the open-phase condition. Under these conditions, BC Hydro experienced a hazardous temporary overvoltage on the open phase in a 287 kV subnetwork. Highly shunt compensated lines have experienced high open phase overvoltage but this incident revealed that transformers in the subnetwork having delta-connected secondary or tertiary windings can also cause this concern. Though it was not designed to do so, the transformer differential protection operated on excessive magnetizing current after the 5th harmonic blocking current dropped below the setting threshold (35%) and prevented damage to the surge arresters. This paper will use disturbance records to recreate the sequence of events and present a detailed waveform analysis. Expected differential relay response when the transformer is severely overexcited will be discussed. A steady-state analysis of the simplified system will be presented, followed by detailed electromagnetic transients simulations which successfully duplicated the disturbance. Based on further simulations, a mitigation plan was developed to avoid a reoccurrence of the problem.