Design of programmable logic device based on electro-optic effect of lithium-niobate-based Mach–Zehnder interferometers

Elastic optical network (EON) technology is considered as a very promising candidate for future high-speed networks due to its intrinsic flexibility and high efficiency in allocating the optical spectrum resources. The key issue that has to be addressed in EON is the routing and spectrum allocation (RSA) problem. RSA is NP-hard problem that has to be solved in an efficient manner. It is a highly challenging task particularly in the case of large problem instances. In this paper, we applied the bee colony optimization (BCO) metaheuristic approach to solve the RSA problem in EON with static traffic demands. The objective of the proposed BCO–RSA algorithm is to minimize both the network spectrum utilization and the average path length criterions. The results of numerous experimental studies show that our BCO–RSA algorithm performs superior compared to some benchmark greedy heuristics as well as to differential evolution (DE) metaheuristic algorithm recently proposed in the literature. The algorithm is evaluated in different realistic size optical networks, such as the NSFnet, two European optical networks (EON-19 and EON-28) and the USA network topology. Simulation results demonstrate that considerable spectrum savings could be achieved with our BCO–RSA algorithm compared to other considered approaches. In addition, we analyzed the efficiency of the BCO–RSA algorithm and compare it with the competitive DE approach according to the required CPU time and the convergence speed.     

SET logic driving capability and its enhancement in 3-D integrated SET–CMOS circuit

The driving capability of a single-electron transistor (SET) circuit is sensitive to the load and interconnects. We discuss about improving the performance of a SET logic in hybrid SET–CMOS circuit by parameter variation and circuit architecture along with its simulation results. With an intention of studying the SET logic drivability in a SET-only circuit, we examined a circuit composed of 2¹³ SET inverters with its interconnect effect in a 3-D CMOS IC. The schematic of the simulation is based on fabrication model of this large circuit along with interlayer and coupling capacitances of its metallization. The simulation results for delay, bandwidth and power validate the efficiency of a SET circuit.     

Design of a 1 × 2 novel optical switch based on polarization converters and splitters

In this paper, a 1?×?2 optical switch based on two TE/TM polarization converters, one 1?×?2-polarization beam splitter and a hybrid 2?×?2-polarization beam splitter/combiner is designed and discussed. The novelty of this work resides in the design of a 2?×?2-hybrid polarization beam combiner/splitter, operating as a 2?×?2 polarization optical switch through the combining and the splitting of polarized signals issued from two TE/TM polarization controllers. The novel hybrid splitter/combiner can route an optical signal either to a bar or a cross port with an extinction ratio higher than 90 dB, thanks to the feature of polarization splitting used in this device to suppress undesired polarization states and minimize the polarization-dependent loss. We have used polarization beam converters to switch between two orthogonal modes in order to facilitate the routing of these signals through the 2?×?2-hybrid polarization splitter/combiner. We changed the polarization states of signals, in our simulation via OptiSystem, through polarization controllers, by modifying only their phase shifts between 0 rad and π rad. The proposed 1?×?2 optical switch presents an average insertion loss of 3.5 dB.

     

Design and simulation of a π/2-mode spatial-harmonic magnetron

Design and 3D numerical simulations of a 37.5 GHz spatial-harmonic magnetron (SHM) are presented. The effect of geometrical parameters of the side resonators of the anode block on output power are considered using the results of a theory based on the single harmonic approximation approach. This theory enables determination of the optimum geometrical parameters of the side resonators. SHM design evaluation is carried out via numerical simulations performed with a 3D particle-in-cell (PIC) code embedded in CST-Particle Studio. Effect of varying the external quality factor and DC-anode voltage on output power, efficiency and stability of operation are also considered. The presented SHM shows stable operation in the π/2-mode over a range of DC anode voltages extending from 12.4 kV to 13 kV and for an axial magnetic flux density equal to 0.53 T. RF output power of the SHM varies from 25 kW to 47 kW over these voltages with a maximum efficiency of around 18.5%.     

Design and analysis of firewall-penetrated scheme based on trusted host

On the basis of various firewall-penetrated technologies, a novel firewall-penetrated technology based on trusted host, which can realize the communication between penetrating host and protected host, is proposed in this paper. Meanwhile, the firewall-penetrated evaluating model and its formalized statement is also proposed by quantizing penetrated level, penetrated quality, and penetrated hiding. Finally, the firewall-penetrated technology based on trusted host is analyzed under the firewall-penetrated evaluating model, and the experimental results show that this technology has obvious penetrating effect and high penetrating quality.     

Design of monostable–bistable transition logic element using the BiCMOS-based negative differential resistance circuit

The monostable–bistable transition logic element (MOBILE) is a promising application for negative differential resistance (NDR) circuit. Previously reported MOBILE is constructed by resonant tunneling diode (RTD) that is implemented by the molecular beam epitaxy (MBE) process. However in this paper, we first propose a NDR circuit composed of standard Si-based metal–oxide–semiconductor field-effect transistor (MOS) and SiGe-based heterojunction bipolar transistor (HBT). Then we demonstrate the inverter, NAND, and NOR gate operations using this MOS–HBT–NDR-based MOBILE circuit. The great advantage of this NDR-based application is that we can implement it using the standard SiGe BiCMOS process without the need for the MBE system.     

Design and Optimization of Quasi–Optical Frequency Multipliers

This paper presents a full–wave algorithm for the design and the optimization of quasi–optical frequency multipliers and discusses its implementation in a specialized computer code, able to simulate as a whole the non–linear device, the planar antenna and the embedding layered structure. The electromagnetic analysis of the multiplier is performed under the simplifying approximation of an infinite array excited by a uniform plane wave incident from the broadside direction. The array parameters are deduced from a full–wave analysis, based on the Method of the Moments, while the solution of the non–linear circuit is found by the Harmonic Balance Method.     

Design of band–notched UWB antenna using a hybrid optimization based on ABC and DE algorithms

In this study, a novel UWB antenna with dual band–rejection is designed by using a new hybrid optimization algorithm based artificial bee colony algorithm (ABC) and differential evolution (DE). The hybrid performance of ABC and DE (H–ABCDE) is tested on well–known benchmark functions. To show its performance on a design problem, an optimization interface (OI) which simultaneously communicates with H–ABCDE and an electromagnetic simulation tool is developed. Hence OI integrating H–ABCDE and HyperLynx® 3D EM is used to design and optimize an antenna. A low profile UWB monopole antenna operating over the frequency range of 2.9–13.0 GHz is then designed through OI. In order to achieve band–rejection operation, various slits and strips have been loaded on the antenna. It thus rejects the dual–band of 3.3–3.6 GHz and 5.15–5.825 GHz corresponds to the operation bands of WLAN and WiMAX. Furthermore, the optimized antenna is prototyped to investigate the measurement performance and it is compared with several designs in the literature. Therefore, H–ABCDE can successfully adapt to the extended electromagnetic problem as well as engineering optimization tasks.     

Design and implementation of high-speed real-time data acquisition system based on FPGA

1 Introduction Electromagnetic radiation will be generated when an electric device, especially video display unit, works, and can give rise to electromagnetic leakage. When the electromagnetic leakage is recognized, the available information can be recove…     

Compact electro-optical programmable logic device based on graphene–silicon switches

Photonic Network Communications - A compact electro-optical programmable logic device (PLD) which can provide any of 16 possible minterms of four Boolean variables on an optical signal is...     

High open-circuit voltage polymer solar cells based on D–A copolymer of indacenodithiophene and fluorine-substituted benzotriazole

A medium band gap D–A copolymer of indacenodithiophene (IDT) and fluorinated dithienylbenzotriazole (FBTA), PIDT-FBTA, was synthesized for the application as donor material in polymer solar cells (PSCs). PIDT-FBTA showed deeper highest occupied molecular orbital (HOMO) energy level due to the strong electron-withdrawing difluorine substitution on benzotriazole acceptor unit in the D–A copolymer. The PSCs based on PIDT-FBTA:PC₇₀BM (1:3) exhibited a high V_oc of 0.90 V and a power conversion efficiency (PCE) of 3.62% under the illumination of AM 1.5G, 100 mW cm⁻². The device performance was further improved by methanol treatment with PCE increased to 4.90% and V_oc increased to 0.92 V.     

A novel Sigma–Delta based parallel analogue-to-residue converter

An important step in the residue number system (RNS) based signal processing is the conversion of signal into residue domain. Many implementations of this conversion have been proposed for various goals, and one of the implementations is by a direct conversion from an analogue input. A novel approach for analogue-to-residue conversion is proposed in this research using the most popular Sigma–Delta analogue-to-digital converter (SD-ADC). In this approach, the front end is the same as in traditional SD-ADC that uses Sigma–Delta (ΣΔ) modulator with appropriate dynamic range, but the filtering is done by a filter implemented using RNS arithmetic. Hence, the natural output of the filter is an RNS representation of the input signal. The resolution, conversion speed, hardware complexity and cost of implementation of the proposed ΣΔ based analogue-to-residue converter are compared with the existing analogue-to-residue converters based on Nyquist rate ADCs.     

Design and Optimization of a novel structure for efficient side-coupling of high power double-cladding fiber lasers

A novel structure for efficient side-coupling of high power double-cladding fiber lasers is presented. The maximum cou- pling efficiency of this structure is more than 90% for TM-polarization in the 1 and -1 order but is only 40% for TE- polarization. Thus, a multi-layer stair-structure is introduced and optimized by combining transmission algorithm and genetic algorithm to obtain higher coupling efficiencyηfor TE-polarization and the maximum coupling efficiency almost reaches to 70%.     

Biomimetic and Biophilic Design of Multifunctional Symbiotic Lichen–Schwarz Metamaterial

Noise and environmental problems are significant issues that affect human beings through the triggering of various stressors, including biological, chemical, physical, and psychological stressors. To address these issues, it is essential to develop environmentally friendly strategies, particularly in the field of materials manufacturing. This study presents a novel biomimetic and biophilic design of a lichen–Schwarz metamaterial (SLSM) that achieves multifunctional properties in noise attenuation and humidity control. The SLSM achieves acoustic and air humidifying multi-functions symbiotically through the use of triply periodic minimal surface (TPMS) and naturally occurring organic lichen. To attain partial or complete sound-blocking capabilities at specific frequencies, a Schwarz meta-symbiont in SLSM requires a parametric design of unit cell characteristics prior to 3D printing. The SLSM structure mimics a biomimetic shell and meta-symbiotic exoskeleton that safeguards the inner symbiont lichen by transitioning it from a dry and brittle state to a hydrated and flexible state during humidity control. The symbiotic lichen in SLSM offers superior sound attenuation across a broader frequency range and adds a unique function of humidity control, which is essential for sustainable architecture and multifunctional furniture in the forthcoming era of buildings.     

Linear and propeller-like fluoro-isoindigo based donor–acceptor small molecules for organic solar cells

Two donor–acceptor type fluoro-isoindigo based small molecule semiconductors are synthesized and their optical, electrochemical, thermal, and charge transport properties are investigated. The two molecular chromophores differ by their architecture, linear (M1) vs propeller-like (M2). Both molecules present a broad absorption in the visible range and a low optical HOMO–LUMO gap (∼1.6 eV). AFM images of solution-processed thin films show that the trigonal molecule M2 forms highly oriented fibrils after a few seconds of solvent vapor annealing. The materials are evaluated as electron donor components in bulk heterojunction organic solar cells using PC₆₁BM as the electron acceptor. The devices based on the propeller-like molecule M2 exhibit a high open-circuit voltage (around 1.0 V) and a power conversion efficiency of 2.23%.     

Design of integrated and autonomous conductivity–temperature–depth (CTD) sensors

Impedance characterization of interfaces is a basic technique for a large class of chemical and biological sensors. This technique is often used to model interfaces between ion-based and electron-based conductive materials by means of electric variables such as voltage, current and charge. Conductivity–temperature–depth (CTD) sensors are sophisticated devices used in the environmental monitoring field to understand the effects of climate changes on oceans and on marine organisms. They usually require impedance sensing as readout technique. High-accuracy CTD sensors are present on the market but they are bulky and power hungry. However, the downscale of modern CMOS technology allows shrinking very complex bioelectronic interfaces into millimeter square size systems, thus opening a large ground of applications. This paper will describe an IC architecture and the related design approach to implement an electrochemical impedance spectroscopy (EIS) technique for CTD sensing and will propose a general approach for sensing complex impedance with low power consumption and high precision. The presented system is designed to achieve 15-bit resolution and power consumption to ensure lifetime up to 1 year using button-size batteries in ocean environment.     

Design and Qualification of Pr–Fe–Cu–B Alloys for the Additive Manufacturing of Permanent Magnets

The direct use of an advanced binder-free additive manufacturing technique, namely laser powder bed fusion (L-PBF), does not easily allow obtaining variously shaped, fully dense Nd–Fe–B magnets with high coercivity. The process inherently leads to the re-melting of the powder and appearance/disappearance of undesired/desired microstructural features responsible for low and large coercivity. In this work, the development of a useful microstructure responsible for high coercivity in Pr₂₁Fe_73.5Cu₂B_3.5 and Nd₂₁Fe_73.5Cu₂B_3.5 alloys and a possible way to produce fully dense permanent magnets via additive manufacturing processes is demonstrated using: (i) suction casting technique, which provides a high cooling rate and thus similar microstructures as in L-PBF but requires only very small amounts of powder; (ii) conventional L-PBF processing using kg of powder, and (iii) a subsequent annealing treatment that is similar to a conventional sintering treatment. The subsequent heat treatment is necessary to develop high coercivity by forming a novel microstructure: hard magnetic (Nd,Pr)₂Fe₁₄B grains embedded in a matrix of intermetallic (Nd,Pr)₆Fe₁₃Cu phase. Furthermore, it is demonstrated that Pr₂₁Fe_73.5Cu₂B_3.5 exhibits a higher coercivity than Nd₂₁Fe_73.5Cu₂B_3.5 because of a finer and more homogeneous grain size distribution of the Pr₂Fe₁₄B phase. The final L-PBF printed Pr₂₁Fe_73.5Cu₂B_3.5 samples provide a coercivity of 0.75 T.     

Design and Implementation of a Bandpass–Bandpass Diplexer Using Coupled Structures

Wireless Personal Communications - In this paper, a bandpass–bandpass two channels diplexer with operating frequencies of 1.7 GHz and 2.1 GHz is designed and fabricated on RT/duroid...     

Mitigation of channel estimation error in TR–UWB system based on a novel MMSE equalizer

The time reversal (TR) technique combined with the ultra-wideband (UWB) system offers a new potential for decreasing the cost and complexity of the UWB receivers. In spite of TR–UWB's good performance in perfect channel state information (CSI), it is very sensitive to the channel estimation error. The effect of channel imperfection on the TR–UWB system is considered in this paper. At first, based on a minimum mean square error (MMSE) equalizer receiver, a prefilter is calculated in closed form to improve the performance of the TR–UWB system in an imperfect CSI scenario. Furthermore, for comparison purposes, a similar calculation for prefilter is carried out based on a simple matched filter (MF) receiver. Then, in order to improve the MF receiver performance, a two-stage iteration-based algorithm is developed. The initial value for this iteration-based improved algorithm is considered to be a prefilter which is calculated in the TR–UWB system with MMSE equalizer. This optimized algorithm causes the channel estimation error in the TR–UWB system to become zero in some steps. Finally, exhaustive simulations are done to demonstrate the performance advantage attained by the improved algorithm.