Showing papers on "Decoupling (electronics) published in 2021"

Antenna Decoupling by Common and Differential Modes Cancellation

Abstract: In this article, a general decoupling method based on a new perspective of common mode (CM) and differential mode (DM) cancellation is proposed. For two closely spaced antennas, the mutual coupling effect can be analyzed and solved by exciting them simultaneously with in-phase (CM) and out-of-phase (DM) signals. It is theoretically proved that, if CM and DM impedances are the same, the mutual coupling effect between two separated antennas can be totally eliminated. Therefore, we can solve the coupling problem by CM and DM impedance analysis and exploit the unique field properties of characteristic modes to assist in antenna decoupling in a physical intuitive way. To validate the feasibility of this method, two practical design examples, including the decoupling between closely spaced dipole antennas and planar inverted-F antennas, are proposed. Both design examples have demonstrated that the proposed method can provide a systemic design guideline for antenna decoupling and achieve better decoupling performance compared to the conventional decoupling techniques. We forecast the proposed decoupling scheme, with a simplified decoupling procedure, has great potential for the applications of antenna arrays and multi-input multi-output (MIMO) systems.

Decoupling Between Extremely Closely Spaced Patch Antennas by Mode Cancellation Method

Abstract: In this article, an inductance-based decoupling scheme is proposed to reduce the mutual coupling between extremely closely spaced microstrip antennas. The original strong coupling can be effectively suppressed by simply inserting a lumped inductance in between. To offer a systemic design guideline for this decoupling strategy, a mode cancellation method, based on the synthesis of common mode (CM) and differential mode (DM), is proposed. The inserted inductance plays a role of tuning CM and DM impedances to a similar status, which has an equivalent decoupling effect according to the theory of microwave network. Alternatively, the lumped inductance could also be replaced by an inductive connecting strip for a concise topology. To validate the proposed decoupling concept, a prototype is simulated, fabricated, and measured. The experimental results show that the poor isolation of 5 dB is improved to better than 15.4 dB across the entire matched bandwidth of 2.394–2.530 GHz, with an extremely close edge-to-edge distance of $0.016~\lambda _{0}$ and center-to-center distance of $0.44~\lambda _{0}$ . Furthermore, the validation of extending to large-scale 1-D and 2-D arrays is also discussed. Featuring simple structure, compressed dimension, strong-coupling suppression, and good radiation performance, the proposed decoupling scheme possesses promising potential for antenna array applications.

Chinese cities exhibit varying degrees of decoupling of economic growth and CO2 emissions between 2005 and 2015

Abstract: Summary Cities, contributing more than 75% of global carbon emissions, are at the heart of climate change mitigation. Given cities' heterogeneity, they need specific low-carbon roadmaps instead of one-size-fits-all approaches. Here, we present the most detailed and up-to-date accounts of CO2 emissions for 294 cities in China and examine the extent to which their economic growth was decoupled from emissions. Results show that from 2005 to 2015, only 11% of cities exhibited strong decoupling, whereas 65.6% showed weak decoupling, and 23.4% showed no decoupling. We attribute the economic-emission decoupling in cities to several socioeconomic factors (i.e., structure and size of the economy, emission intensity, and population size) and find that the decline in emission intensity via improvement in production and carbon efficiency (e.g., decarbonizing the energy mix via building a renewable energy system) is the most important one. The experience and status quo of carbon emissions and emission-GDP (gross domestic product) decoupling in Chinese cities may have implications for other developing economies to design low-carbon development pathways.

Wideband Decoupling of Integrated Slot Antenna Pairs for 5G Smartphones

Abstract: This communication proposes a wideband decoupling technique to suppress the strong coupling between two extremely closely spaced open-slot antennas and implements a wideband integrated slot antenna pair for fifth-generation (5G) metal-rimmed smartphones. By simply inserting a connecting line between two closely spaced open-slot antennas, a top slot structure can be constituted with odd- and even-mode resonances in the lower and higher bands, respectively, to cancel the original strong mutual coupling. In addition to the decoupling effect, the top slot can also expand the effective radiation aperture of the antenna pair for the bandwidth improvement. The proposed slot antenna pair, with a compact footprint of $28 \,\, \times 7\,\,\times1.8$ mm3, shows good impedance matching, isolated and diversity performance across 3.3–5.0 GHz. Then, an $8 \times 8$ multiple-input multiple-output (MIMO) system, constituted by four sets of slot antenna pairs, is simulated, fabricated, and measured. Both the simulated and experimental results show that the $8 \times 8$ MIMO system can offer isolations of better than 10.8 dB and envelope correlation coefficients (ECCs) of less than 0.14 between all eight ports across 3.3–5.0 GHz. Also, a total efficiency of 55.0%–83.1% and 52.5%–83.1% is achieved for Ant1 and Ant2, respectively. Featuring wide bandwidth, compact size, high integration level, and metal rim compatibility, we forecast the proposed solution has great potential for future 5G smartphones.

How renewable energy reduces CO2 emissions? Decoupling and decomposition analysis for 25 countries along the Belt and Road

Abstract: To explore how renewable energy reduces carbon dioxide (CO2) emissions, this study decomposes the impacts of renewable energy on CO2 emissions by employing the Generalized Divisia Index Method (GDI...

Decoupling the Voltage Hysteresis of Li-Rich Cathodes: Electrochemical Monitoring, Modulation Anionic Redox Chemistry and Theoretical Verifying

Abstract: Cathodes in lithium-ion batteries with anionic redox can deliver extraordinarily high specific capacities but also present many issues such as oxygen release, voltage hysteresis, and sluggish kinetics. Identifying problems and developing solutions for these materials are vital for creating high-energy lithium-ion batteries. Herein, the electrochemical and structural monitoring is conducted on lithium-rich cathodes to directly probe the formation processes of larger voltage hysteresis. These results indicate that the charge-compensation properties, structural evolution, and transition metal (TM) ions migration vary from oxidation to reduction process. This leads to huge differences in charge and discharge voltage profile. Meanwhile, the anionic redox processes display a slow kinetics process with large hysteresis (≈0.5 V), compared to fast cationic redox processes without any hysteresis. More importantly, a simple yet effective strategy has been proposed where fine-modulating local oxygen environment by the lithium/oxygen (Li/O) ratio tunes the anionic redox chemistry. This effectively improves its electrochemical properties, including the operating voltage and kinetics. This is also verified by theoretical calculations that adjusting anionic redox chemistry by the Li/O ratio shifts the TM 3d—O 2p bands and the non-bonding O 2p band to a lower energy level, resulting in a higher redox reaction potential.

A Field Enhancement Integration Design Featuring Misalignment Tolerance for Wireless EV Charging Using LCL Topology

Abstract: This article proposes a magnetic integration design for EV wireless power transfer (WPT) systems, where the compensation and transmitting coils overlap one on top of the other to share the ferrite layer without any decoupling consideration. The magnetic field generated by both the compensation and transmitting coils are exploited to transfer power. To this end, a compensation method is proposed to enable magnetic field enhancement without any reactive power flow between the compensation and the transmitting coils, and to achieve input zero phase angle and constant current output. In addition, an efficient finite element analysis-based coil optimization algorithm is proposed to improve the coil misalignment tolerance on the horizontal plane, in which a reversely connected inner coil is used to stabilize the system output under misalignment conditions. Analytical and simulation results confirm transmission flux density enhancement and reduced leakage field characteristics of the proposed coil design. Finally, a scaled-down WPT prototype is built and tested to verify the performance and effectiveness of the design. The proposed design achieves 91.17% efficiency and misalignment tolerance up to 200 mm in any XY-direction while maintaining the power transfer and its efficiency. The results of this work provide insights into magnetic integration design of high-order compensation topologies featuring higher compactness, less ferrite usage, magnetic field enhancement, and misalignment tolerance for WPT systems.

Do Markets Punish or Reward Corporate Social Responsibility Decoupling

Abstract: This article analyzes the relationship between corporate social responsibility (CSR) decoupling and financial market outcomes. CSR decoupling refers to the gap between CSR disclosure and CSR perfor...

A Low-Profile Decoupling Structure for Mutual Coupling Suppression in MIMO Patch Antenna

Abstract: In this article, a new low-profile decoupling structure originated from the phase shift concept for the patch antenna array is proposed. To clearly illustrate the operation principle, the phase of the signal transmitted from Patch 1 to Patch 2 has been initially studied and the decoupling condition for two closely spaced patch antennas in H-plane has also been obtained. Afterward, the decoupling element concisely composed of a half-wave microstrip line and a shorting pin is developed. Attributing to the introduction of additional signal path by the new decoupling structure, mutual coupling between two adjacent patches is effectively suppressed. To verify the feasibility of the proposed design scheme, demonstrators of two-element patch antennas with and without decoupling structure are, respectively, implemented and analyzed. Results indicate that compared with the coupled array, the isolation between two patch elements is enhanced from 7 to 18 dB at the center frequency of 3.16 GHz under the edge-to-edge separation of only 0.027 $\lambda _{0}$ . Besides, owing to the single layer layout, the profile of the whole antenna structure is as low as 0.02 $\lambda _{0}$ . Ultimately, the proposed decoupling scheme has been applied to the three-element counterpart, so as to demonstrate and validate its effeteness of isolation enhancement for multielement patch array.

Partitional Decoupling Method for Fast Calculation of Energy Flow in a Large-Scale Heat and Electricity Integrated Energy System

Abstract: Wide development of the heat and electricity integrated energy system (HE-IES) has provided flexible multi-energy optimization management, which improves energy efficiency and benefits the environment. It is essential to calculate energy flow quickly, accurately, and reliably as the system scale and complexity increase. To handle this problem, we propose a partitional decoupling method based on a decomposed energy flow model for the large-scale HE-IES. The computation mechanisms are presented considering various system scales and topologies, which consist of decoupling mode to solve the non-convergence caused by hydraulic initialization and the iteration mode to correct the variables at common nodes of decoupled systems. Moreover, a unit conversion method is introduced to solve the non-convergence problem in energy flow calculation under extreme scenarios. Case studies show that the proposed method provides accurate energy flow calculations with higher efficiency regardless of system scale and topology, especially in looped systems. Numerical simulation further verifies the effectiveness of the proposed method for non-convergence.

Power Coupling Mechanism Analysis and Improved Decoupling Control for Virtual Synchronous Generator

Abstract: A virtual synchronous generator (VSG) control-based grid-connected converter (GCC) is an attractive solution to improve the stability of a more renewable-energy-integrated power system. Unfortunately, the inherent power coupling (i.e., the interaction between the active power loop and the reactive power loop) defect of VSG control severely restricts the power delivery capacity and the grid support capability of the GCC. The virtual inductor is commonly used to reduce coupling, but its decoupling capability is very limited. In addition, the power coupling mechanism and its limiting factors are not clear. For this issue, the nature of power coupling in the VSG system is investigated first. The decoupling capability of the virtual inductor is studied, and the reason for decoupling effectiveness is revealed. It indicates that the effectiveness of decoupling results from the proper voltage compensation, but this kind of positive effect is limited by the d -axis voltage drop across the virtual inductor. Then, a q -axis voltage-drop-based power decoupling control (QVPDC) is proposed to further reduce the power coupling, which does not consider the d -axis voltage drop when applying the virtual inductor. Compared with the virtual-inductor-based decoupling method, the decoupling performance of QVPDC is better, and the computation burden is reduced by half. Finally, the analysis and the proposed method are validated by simulation and experiment.

Decoupling and decomposition analysis of environmental impact from economic growth: a comparative analysis of Pakistan, India, and China

Abstract: The dispute between economic growth and greenhouse gas emissions is one of the major challenges of the twenty-first century. The central issue of the emerging economies revolves around the decoupling of economic growth and the rising carbon dioxide (CO2) emissions. This study examines the decoupling the CO2 emissions from the economic growth through the employment of the Tapio decoupling index and decomposition of CO2 emissions into its pre-determined factors through the Log Mean Divisia Index (LMDI) decomposition technique for Pakistan, India, and China (PIC) for a time span of 1990–2014. The findings of the Tapio elasticity analysis depict that in a few years, environmental impact has been seen to be decoupled from the economic growth in the respective PIC countries. However, relatively Pakistan experienced expensive negative decoupling; India mostly experienced weak decoupling and expensive coupling, while China exhibited weak decoupling in multiple years. In addition, the analysis of Tapio decoupling elasticity showed that energy intensity is the key factor supporting the decoupling in PIC countries, while population, affluence (GDP per capita) and energy structure have weakened the progress of decoupling. Furthermore, the analysis of the LMDI decomposition suggested that population, energy structure and affluence in PIC countries increase the CO2 emissions, while energy intensity reduces CO2 emissions, while mixed effects are reflected by carbon intensity.

High-order fully-actuated system approaches: Part VI. Disturbance attenuation and decoupling

Abstract: Two types of high-order fully actuated (HOFA) system models subject to external disturbances are firstly introduced. For the type of HOFA systems with deterministic disturbances, the problem of dis...

Isolation Enhancement for MIMO Patch Antennas Sharing a Common Thick Substrate: Using a Dielectric Block to Control Space-Wave Coupling to Cancel Surface-Wave Coupling

Abstract: This article presents a novel and simple decoupling method to increase the isolation between two closely spaced patch antennas sharing a common thick substrate. The decoupling can be simply realized by adding a pure dielectric block (DB) above the coupled array. By means of DB to modify the space permittivity (propagation constant), the space-wave coupling can be controlled to cancel surface-wave coupling for isolation enhancement. Five benchmarks of combinations of two patch antennas with different positions or orientations are investigated to validate the decoupling concept and elaborate on the design procedure. The results show that the proposed method could provide over 20 dB isolation enhancements for patch antennas with $0.1\lambda _{0}$ or $0.027\lambda _{0}$ separation distances. Besides, wide isolation bandwidths and good radiation performances can be achieved for the DB-loaded antennas without reduction in total efficiency, front-to-back ratio (FBR), boresight gain, or polarization purity. Notably, the DB can be designed independently of the original array, making this method potential for some previously fabricated arrays without requiring modifying or replacing them with new ones.

A Simple Decoupling Network With Filtering Response for Patch Antenna Arrays

Abstract: Facing the demand for decoupling and filtering for large-scale antenna arrays in modern communication systems, a transmission-line-based scheme is proposed and studied in this article. Different from other decoupling networks published recently featuring narrow decoupling bandwidths and high spurious levels, the proposed approach uses simple T-shaped networks where decoupling and filtering responses are realized simultaneously, leading to high-frequency selectivity and improved decoupling bandwidth. The proposed design is a simple 1-D configuration but powerful for 2-D arrays. Based on the study case of a $4\times {4}$ dual-polarized patch array, theoretical analysis and full-wave simulation are carried out to verify the performance in decoupling and frequency selectivity of this method. A prototype is further fabricated, assembled, and measured to demonstrate the performance of the proposed method in practice. The measured and simulated results are consistent with each other where a low insertion loss of around 0.6 dB is observed. The results denote that the proposed method is easily realized with a very small effect on the radiation performance of antenna elements, making it to be a potential and valuable decoupling and filtering solution for large-scale arrays.

Provincial CO 2 Emission Measurement and Analysis of the Construction Industry under China’s Carbon Neutrality Target

Abstract: The construction industry plays a crucial role in China’s fulfillment of the goal of achieving “carbon neutrality” in 2060 Based on the data of energy and building materials consumption of the construction industry in China and 30 provinces from 2008 to 2018, this paper constructs a model for measuring provincial CO2 emissions of China’s construction industry and establishes a Kuznets curve and elastic decoupling model of the industry’s CO2 emissions The analysis based on the models shows that: (1) the CO2 emissions of China’s construction industry show a trend of increasing first and then decreasing; (2) in terms of the decoupling effects, most provinces are in a weak decoupling status of CO2 emissions; and (3) the Kuznets curve of the provincial construction industry shows an inverted “U” shape in recent years, and it is predicted that the CO2 emissions of the construction industry will reach the peak in 2034 It is possible for the construction industry to achieve “carbon neutrality”, but long-term efforts must be made for strategic planning, policies and regulations, industry standards, etc

An Input–Output Feedback Linearization Control Method Synthesized by Artificial Neural Network for Grid-Tied Packed E-Cell Inverter

Abstract: In this article, a trained artificial neural network (ANN) input–output feedback linearization (IOFL) control strategy is proposed for a grid-connected nine-level packed E-cell (PEC9) converter under various operating variations. For the first time, a second-order dynamic model in d–q reference frame is developed for PEC9 converter. This model enforces the converter to employ IOFL-based proportional–resonance compensators for accurately contributing to current tracking enhancement, mitigation at the current ripple, and consequently, the capacitors dc voltages ripple. As another contribution, the current tracking ability of the proposed controller is much more promoted by decoupling the d–q dynamic components. Indeed, the effect of each proposed control component is fortified through decoupling feedback coefficients. In addition, as the third contribution, ANN as the complementary controller adapts the proposed IOFL-based controller coefficients to improve efficiency and stability of the whole control loop system, including the PEC9 capacitor voltages in unstable operation of load, grid, and dc source as well as in the presence of parameters mismatch and disturbances. To support the aforementioned contributions with more details, the closed-loop description and the dynamic model of the proposed controller-based PEC9 converter are utilized to present several stability evaluation processes in both time and frequency domains. This assessment process is accurately executed to confirm the stable performance of PEC9 when the errors of the PEC9 converter currents are changed as well as the decoupling feedback coefficients are varied. Finally, comparative dSPACE setup-based experimental and simulation results are attained to further verify the validity of the proposed control strategy under various operating conditions.