Multiport Network Research Articles

Design of Reconfigurable Intelligent Surfaces by Using S-Parameter Multiport Network Theory—Optimization and Full-Wave Validation

Design of Reconfigurable Intelligent Surfaces by Using <i>S</i>-Parameter Multiport Network Theory—Optimization and Full-Wave Validation

Performance-constrained multi-objective optimization of antennas for miniaturization design

The miniaturization of antennas is crucial as it improves the integration of wireless communication system. In order to achieve miniaturization of antennas, a performance-constrained multi-objective optimization method (PCMOM) considering the size and return loss is proposed. In the PCMOM method, an optimization strategy based on a multi-port network model is introduced, enabling the formation of antennas with various structures. Furthermore, we integrate the constraint of return loss performance into the non-dominated sorting genetic algorithm II (NSGA-II), eliminating solutions that do not meet performance requirements. Three pixel antennas are designed using the PCMOM method and two of them are fabricated. Experimental results demonstrate that the proposed PCMOM method can effectively address the complex trade-off issues in antenna miniaturization design.

ECONOMIC BENEFITS OF DEPLOYING FOLDABLE CONTAINERS: REDUCING BUNKER AND CONTAINER MANAGEMENT COSTS IN A MULTI-PORT SHIPPING NETWORK

This study seeks to explore the effectiveness of employing foldable containers (FLDs) in liner shipping to reduce relocation and the empty containers and bunker costs (BCs) associated with ship operations. This resolves a minimum-cost multi-commodity network flow problem by optimizing container fleet size and empty container relocation in a multi-port shipping service network. Port handling time and sailing speed provided by obtained optimal solutions enable the determination of ship BCs as a secondary step. The numerical experiments demonstrate the comparative effect of FLDs against standard ones on the reduction of the costs of empty containers and containership bunker oil.

A Novel Two-Stage Optimization Framework for Designing Active Metasurfaces Based on Multiport Microwave Network Theory

A Novel Two-Stage Optimization Framework for Designing Active Metasurfaces Based on Multiport Microwave Network Theory

Accurate Multiport Network Model for Forced Oscillations Analysis and Suppression of Multichip IGBT Power Modules

Accurate Multiport Network Model for Forced Oscillations Analysis and Suppression of Multichip IGBT Power Modules

Design and Analysis of Irregular Hexagonal Patch Antenna Using Multiport Network Model (MNM)

Design and Analysis of Irregular Hexagonal Patch Antenna Using Multiport Network Model (MNM)

Low Phase Noise Differential and Push-Pull Oscillators Based on SIW Multiport Network

Low Phase Noise Differential and Push-Pull Oscillators Based on SIW Multiport Network

A general configuration for nonlinear circuit employing current-controlled nonlinearity: Application in Chua’s circuit

In this paper, a general configuration for nonlinear circuit employing current-controlled nonlinearity is proposed, which has a simple topology and only contains three linear energy storage components, one nonlinear element, and one multi-port network that can be made by linear resistor. Under this configuration, we design two new five-element chaotic circuits including the first third-order one employing a current-controlled anti-parallel connection diode pair and the second fourth-order one employing a current-controlled memristor emulator. The analyses show that the third-order chaotic circuit is dual to the canonical Chua’s circuit, and the extended fourth-order one can be regarded as a dual canonical memristive Chua’s circuit. The basic analyses including the model description, equilibrium point and stability are presented. Several rich dynamical properties of the two chaotic circuits are investigated using numerical simulations and certified by both Pspice circuit simulations and analog circuit measurements.

Calibration and efficient evaluation of electromigration lifetime for interconnect wire sizing of multi-port networks

A canonical form of the hydrostatic stress equations for electromigration is proposed to determine the minimum number of parameters to calibrate the model. An efficient probabilistic lifetime checker is developed to determine the wire sizing of interconnect segments. Large networks can be checked on a segment-by-segment basis. To enable efficient evaluation of lifetime, multivariate models are constructed by precomputing the results for all possible interconnect segment geometries, model parameters, and current densities.

Beyond Diagonal Reconfigurable Intelligent Surfaces: A Multi-Sector Mode Enabling Highly Directional Full-Space Wireless Coverage

Reconfigurable intelligent surface (RIS) has gained much traction due to its potential to manipulate the propagation environment via nearly-passive reconfigurable elements. In our previous work, we have analyzed and proposed a beyond diagonal RIS (BD-RIS) model, which is not limited to traditional diagonal phase shift matrices, to unify different RIS modes/architectures. In this paper, we create a new branch of BD-RIS supporting a multi-sector mode. A multi-sector BD-RIS is modeled as multiple antennas connected to a multi-port group-connected reconfigurable impedance network. More specifically, antennas are divided into <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> ≥ 2) sectors and arranged as a polygon prism with each sector covering 1/ <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> space. Different from the recently introduced concept of intelligent omni-surface (or simultaneously transmitting and reflecting RIS), the multi-sector BD-RIS not only achieves a full-space coverage, but also has significant performance gains thanks to the highly directional beam of each sector. We derive the constraint of the multi-sector BD-RIS and the corresponding channel model taking into account the relationship between antenna beamwidth and gain. With the proposed model, we first derive the scaling law of the received signal power for a multi-sector BD-RIS-assisted single-user system. We then propose efficient beamforming design algorithms to maximize the sum-rate of the multi-sector BD-RIS-assisted multiuser system. Simulation results verify the effectiveness of the proposed design and demonstrate the performance enhancement of the proposed multi-sector BD-RIS.

Research on Multi-Port Ship Traffic Prediction Method Based on Spatiotemporal Graph Neural Networks

The intelligent maritime transportation system has emerged as a pivotal component in port management, owing to the rapid advancements in artificial intelligence and big data technology. Its essence lies in the application of digital modeling techniques, which leverage extensive ship data to facilitate efficient operations. In this regard, effective modeling and accurate prediction of the fluctuation patterns of ship traffic in multiple port regions will provide data support for trade analysis, port construction planning, and traffic safety management. In order to better express the potential interdependencies between ports, inspired by graph neural networks, this paper proposes a data-driven approach to construct a multi-port network and designs a spatiotemporal graph neural network model. The model incorporates graph attention networks and a dilated causal convolutional architecture to capture the temporal and spatial dimensions of traffic variation patterns. It also employs a gated-mechanism-based spatiotemporal bi-dimensional feature fusion strategy to handle the potential unequal relationships between the two dimensions of features. Compared to existing methods for port traffic prediction, this model fully considers the network characteristics of the overall port and fills the research gap in multi-port scenarios. In the experiments, real port ship traffic datasets were constructed using data from the Automatic Identification System (AIS) and port geographical information data for model validation. The results demonstrate that the model exhibits outstanding robustness and performs well in predicting traffic in multiple sub-regional port clusters.

Model Order Reduction of Cage Induction Motor With Skewed Rotor Slots Using Multiport Cauer Ladder Network Method

A method for efficiently deriving a reduced-order model of a cage induction motor (IM) with skewed rotor slots is proposed based on the multiport Cauer ladder network (CLN) method. This paper presents several formulations of the multiport CLN method for the skewed rotor, in which the continuity of the bar currents and the space harmonics included in the air-gap flux density waveform are treated differently. The effectiveness of the developed methods was verified from the viewpoints of computational accuracy and cost through application to a practical cage IM with skewed rotor slots.

Direct Synthesis of Acoustic Wave Multiplexers Built on Fully Canonical Multiport Functions

This work proposes the first analytical method for the direct synthesis of multiplexers based on acoustic wave (AW) ladder filters connected in a star junction topology. It describes the computation of the polynomial representation of a multiport ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K} +$ </tex-math></inline-formula> 1 ports) network with fully canonical (FC) channels and derives a set of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}$ </tex-math></inline-formula> distorted channel polynomials from which each of the AW ladder filters is synthesized. The channel polynomials are distorted in a way such that when connected together at the star junction, the desired multiplexer response is obtained avoiding degradation due to channel loading. The method allows to freely set the fractional bandwidth (FBW), return loss (RL), and transmission zeros (TZs) of each channel enabling the search for multiplexers that fulfill the technological requirements of AW technology in terms of electromechanical coupling coefficient and area occupancy among others. Moreover, since the multiport network polynomials incorporate the complete effects of the loading between channels as, for example, additional TZs, the synthesized multiplexers depict an improvement of isolation when compared with a design based on only controlling the reflection phase of each channel filter. The proposed method is rigorously demonstrated by means of a synthesized multiplexer example providing the Butterworth–Van Dyke (BVD) elements of each channel filter. This approach avoids intensive optimization procedures and represents a useful technique for the design of carrier aggregation (CA) filter modules in a direct and controlled manner.

Broad-Angle Multichannel Metagrating Diffusers

We present a semianalytical scheme for the design of broad-angle multichannel metagratings (MGs), sparse periodic arrangements of loaded conducting strips (meta-atoms), embedded in a multilayer printed circuit board (PCB) configuration. By judicious choice of periodicity and angles of incidence, scattering off such an MG can be described via a multiport network, where the input and output ports correspond to different illumination and reflection directions associated with the same set of propagating Floquet–Bloch (FB) modes. Since each of these possible scattering scenarios can be modeled analytically, constraints can be conveniently applied on the modal reflection coefficients (scattering matrix entries) to yield a diffusive response, which, when resolved, produce the required MG geometry. We show that by demanding a symmetric MG configuration, the number of independent S parameters can be dramatically reduced, enabling satisfaction of multiple such constraints using a single sparse MG. Without any full-wave optimization, this procedure results in a fabrication-ready layout of a multichannel MG, enabling retroreflection suppression and diffusive scattering from numerous angles of incidence simultaneously. This concept, verified experimentally via a five-channel MG prototype, offers an innovative solution to both monostatic and bistatic radar cross Section (RCS) reduction, avoiding design and implementation challenges associated with dense metasurfaces used for this purpose.

Data set for Reduction of Multi-Port Water Distribution Networks using the Generalized Thevenin Theorem

Data set for Reduction of Multi-Port Water Distribution Networks using the Generalized Thevenin Theorem

Realizable Reduction of Multi-Port RCL Networks by Block Elimination

In this paper a block circuit elimination method is proposed for realizable reduction of resistor-capacitor-inductor (RCL) networks. It is an extension of a recently published realizable RC reduction method, called HD-TICER (high-dimensional time-constant equilibration reduction), to reduction of multi-port RCL networks. A modified nodal analysis (MNA) formulation is adopted in a setting for dealing with the inductive elements, which is suited for developing a realizable high-dimensional reduction scheme. A new matrix-based method is presented to establish the basic computation scheme, which seems more intuitive than the previously employed driving point impedance (DPI) method. Furthermore, a pole-zero based low-order moment matching method is introduced for the purpose of circuit recovery after reduction. The main advantages of the proposed reduction method include: 1) an intuition-based topological formulation and reduction computation method, 2) a natural port preserving reduction method, and 3) an easy-to-implement circuit recovery procedure. Experimental numerical implementation has validated the effectiveness of the proposed reduction method. Comparison to other existing methods further highlights multiple benefits of this new circuit reduction method.

Orthogonal rational approximation of transfer functions for high‐frequency circuits

SummaryThis paper introduces the orthogonal rational approximation (ORA) algorithm for rational function approximation of transfer functions, based on data available from simulations or measurements. A rational function allows integration of such data in transient solvers for analysis of high‐frequency circuits. In rational function approximation, the unknown denominator polynomial of the model results in a nonlinear problem, which can be replaced with successive solutions of linearized problems following the Sanathanan–Koerner (SK) iteration. An orthogonal basis can be obtained based on Arnoldi resulting in a stabilized SK iteration. We present an extension of the stabilized SK, called ORA, which ensures real polynomial coefficients and stable poles for realizability of electrical networks. We also introduce an efficient implementation of ORA for multiport networks based on a block QR decomposition.

High-Gain Dual-Mode Cylindrical Rectangular Patch Antenna for Airborne Applications

This article presents a conformal antenna system for providing a dual-band high-gain communication link between an unmanned aerial vehicle (UAV) and a ground station where the two bands can be used independently for command-control and data link. A cylindrically conformal rectangular patch antenna operating in the higher order TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">03</sub> modes is proposed, which produces high gain in both the frequency bands. This is possible by loading the cylindrical–rectangular patch antenna by a centrally located slot, which makes the radiation pattern of the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> mode broadside radiating and lowers the sidelobe level of the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">03</sub> mode. Multiport network modeling (MNM) of the structure is done, which leads to the optimum design, and the effect of curvature on antenna performance is also studied. As the antenna has around 60° beamwidth in one of the planes for both the frequency bands, three such antennas are placed on one arm of a quadcopter UAV so that 180° coverage can be obtained by switching the antennas. The antenna system has a simulated gain of 7.94 and 10.21 dBi at 10.288 and 12.412 GHz, respectively. A single slot-loaded cylindrical–rectangular patch antenna is fabricated and the measured results are compared with those obtained by MNM and simulation. The antenna gives a gain of 7.46 and 9.83 dBi at the frequencies of 10.323 and 12.46 GHz, respectively.

Generalized multimode scattering parameters and the applications in antenna and radio frequency component designs

This article applies the generalized multimode S-parameters to multiport antennas and radio frequency (RF) components for CAD applications. Consider the special case of impedance matching which could significantly simplify the multimode representation on port and remove the requirement on calculating port impedance. N single-ended ports of a network are regarded as one generalized multimode port, supporting N orthonormal modes represented by N orthonormal basis vectors, respectively. By doing this, in antenna and RF component designs, one can only focus on specific modes interested, while ignore others. A multiport network's characteristics could be represented and understood in a much simpler manner because fewer but more intuitive physical quantities are considered. Therefore, this can significantly simplify the analysis, design, and optimization of multiport networks. For better illustration, several examples, including branch-line coupler, mixed-mode case, sequential rotation feeding antenna, and monopulse feed are analyzed and designed. Complicated analyses in network design using the single-ended S-parameters, including matching, amplitude and phase unbalance, could be converted into much simpler ones from the generalized multimode perspective.

Nonlinear Model Order Reduction of Induction Motors Using Parameterized Cauer Ladder Network Method

In this study, we established the nonlinear model order reduction (MOR) of induction motors by parameterizing a multi-port Cauer ladder network (CLN). Appropriate parameters were selected to incorporate nonlinear magnetic characteristics. The parameterized multi-port CLN was applied to the transient analysis of a rotating induction motor. The proposed method reproduced the finite-element analysis results with various driving frequencies and slips. The parameterized multi-port CLN can effectively reduce the computation time for analyses requiring a large number of time steps.