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Impedance Mismatch Effects In Microstrip And Stripline Ebg Common-Mode Filters, Marina Y. Koledintseva, Sergiu Radu, Joe Nuebel
Impedance Mismatch Effects In Microstrip And Stripline Ebg Common-Mode Filters, Marina Y. Koledintseva, Sergiu Radu, Joe Nuebel
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, impedance mismatch effects on the characteristics of common-mode (CM) electromagnetic bandgap (EBG) filters are studied using 3D full-wave numerical simulations. Herein, the terminations are fixed at 50 Ohms, and the effect of the differential line impedance variations are studied. Two types of CM EBG filters are considered in this work, both are designed using standard printed circuit board technology. The first group contains microstrip (MS) differential pairs running above the EBG plane, and the second group contains strip line (SL) differential pairs running on one of the layers next to the EBG plane. It is shown that …
A Novel Data-Driven Analysis Method For Nonlinear Electromagnetic Radiations Based On Dynamic Mode Decomposition, Yanming Zhang, Lijun Jiang
A Novel Data-Driven Analysis Method For Nonlinear Electromagnetic Radiations Based On Dynamic Mode Decomposition, Yanming Zhang, Lijun Jiang
Electrical and Computer Engineering Faculty Research & Creative Works
Nonlinear effects generated in complex electronic systems such as cell phones and computers cause broadband electromagnetic radiations. They are very difficult to model but could be key contributors to the radiated spurious emission (RSE) and radio frequency interference (RFI). In this paper, a novel data-driven characterization method is proposed to analyze the transient responses of the nonlinear circuits and their nonlinear electromagnetic radiations. It employs the dynamic mode decomposition (DMD) to simultaneously extract the temporal patterns and their corresponding dynamic modes. The temporal patterns show high order harmonics generated by the nonlinearity. Then these temporal spatial coherent patterns could provide …
Fully Adaptive Cloud Profiling Radar Simulation, J. Delong, M. A. Shattal, A. O'Brien, C. D. Ball, J. T. Johnson, G. E. Smith
Fully Adaptive Cloud Profiling Radar Simulation, J. Delong, M. A. Shattal, A. O'Brien, C. D. Ball, J. T. Johnson, G. E. Smith
Electrical and Computer Engineering Faculty Research & Creative Works
This paper demonstrates how the fully adaptive radar framework can be applied to cloud profiling radars. A simulation based on the GEOS5 nature run dataset is introduced in which the cloud profiling radar continuously adapts its pulse repetition frequency (PRF) such that the unambiguous range is 1.2 times the cloud column height. This process maximizes the (PRF) which would in turn maximize the unambiguous velocity estimate.
Distributed State Estimation By Using Active-Passive Sensor Networks, Akhilesh Raj, S. Jagannathan, Tansel Yucelen
Distributed State Estimation By Using Active-Passive Sensor Networks, Akhilesh Raj, S. Jagannathan, Tansel Yucelen
Electrical and Computer Engineering Faculty Research & Creative Works
This paper proposes a novel adaptive observer for heterogeneous sensor networks (HSNs) to estimate state vector of an unknown target or process by using the sensed output when the input to the target/process is also not known. In an HSN, nodes are considered either active or passive depending upon their ability to sense the target output. The local information exchange among the nodes is dictated by a connected graph. By using the criterion of collective observability, a novel distributed adaptive estimation is introduced where the nodes are allowed to have different sensor modalities. Stability analysis shows uniform ultimate boundedness of …
Real‐Time Overhead Power Line Sag Monitoring, Jie Huang, Rui Bo
Real‐Time Overhead Power Line Sag Monitoring, Jie Huang, Rui Bo
Electrical and Computer Engineering Faculty Research & Creative Works
System and method for determining real-time sag and shape information of an electrical power line based on strain distribution along a length of an optical fiber associated with the power line. An embedded fiber coupled to an overhead transmission line measures strain using the backscatter of an optical signal, the optical signal is then interrogated using an interferometer.
Post Deposition Annealing Effect On Properties Of Y 2 O 3 /Al 2 O 3 Stacking Gate Dielectric On 4h-Sic, Feng Zhao, Oliver Amnuayphol, Kuan Yew Cheong, Yew Hoong Wong, Jheng Yi Jiang, Chih Fang Huang
Post Deposition Annealing Effect On Properties Of Y 2 O 3 /Al 2 O 3 Stacking Gate Dielectric On 4h-Sic, Feng Zhao, Oliver Amnuayphol, Kuan Yew Cheong, Yew Hoong Wong, Jheng Yi Jiang, Chih Fang Huang
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, the effect of post deposition annealing (PDA) on the chemical, structural, and electrical properties of the high-kY2O3 /Al2O3 stacking dielectric on p-type 4H-SiC were studied. High-k dielectric provides a physically thicker film with equivalent capacitance, therefore better exploits the high breakdown strength of 4H-SiC in its MOSFET devices. The Y2O3 /Al2O3 stacking films were deposited using RF magnetron sputtering, with PDA in Ar ambient at 400 °C, 600 °C, 800 °C and 1000 °C. X-ray diffraction (XRD) and angle resolved X-ray photoelectron spectroscopy (XPS) results …
Systems And Methods For Single-Element Beam Steering Antennas, Haozhan Tian, Lijun Jiang, Tatsuo Itoh
Systems And Methods For Single-Element Beam Steering Antennas, Haozhan Tian, Lijun Jiang, Tatsuo Itoh
Electrical and Computer Engineering Faculty Research & Creative Works
Systems and methods for single element beam steering antennas are provided. One embodiment includes: a first and second radiating resonant cavities, where the first and second radiating resonant cavities are coupled together; and at least one tunable component; where the first and second radiating resonant cavities, and the at least one tunable component are configured, in combination, to form a beam toward a desired direction, and where the at least one tunable component is configured to set the desired direction by an application of a bias voltage on the at least one tunable component.
Antennas And Related Methods For Realizing Endfire Radiation With Vertical Polarization, Haozhan Tian, Lijun Jiang, Tatsuo Itoh
Antennas And Related Methods For Realizing Endfire Radiation With Vertical Polarization, Haozhan Tian, Lijun Jiang, Tatsuo Itoh
Electrical and Computer Engineering Faculty Research & Creative Works
Apparatus and systems for antennas for end fire radiation with vertical polarization are described. In an embodiment, an antenna includes a top patch, a ground substrate defining a hole, a feeding cable disposed to mate with the hole, two coupled radiating resonant cavities having two eigen-modes, where the coupled radiating resonant cavities are configured to form a beam, and where the antenna is configured for end fire radiation with vertical polarization.
Silicon Nitride Stress Liner Impacts On The Electrical Characteristics Of Algan/Gan Hemts, Wei Chih Cheng, Tao Fang, Siqi Lei, Yunlong Zhao, Minghao He, Mansun Chan, Guangrui Maggie Xia, Feng Zhao, Hongyu Yu
Silicon Nitride Stress Liner Impacts On The Electrical Characteristics Of Algan/Gan Hemts, Wei Chih Cheng, Tao Fang, Siqi Lei, Yunlong Zhao, Minghao He, Mansun Chan, Guangrui Maggie Xia, Feng Zhao, Hongyu Yu
Electrical and Computer Engineering Faculty Research & Creative Works
Due to the piezoelectric nature of GaN, the two-dimensional electron gas (2DEG) in AlGaN/GaN high electron mobility transistor (HEMT) could be engineered by strain. In this work, SiNx deposited using dual-frequency plasma-enhanced chemical vapor deposition (PECVD) was used as a stressor. The output performance of the devices was dominated by the surface passivation instead of the strain effect. However, the threshold voltage was increased by the liner-induced strain, supporting strain engineering as an effective approach to pursue the normally-off operation of AlGaN/GaN HEMTs.
Analysis Of The Topological Photonic Crystals Using Finite-Difference Supercell Approach, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Zhihao Lan, Wei E.I. Sha
Analysis Of The Topological Photonic Crystals Using Finite-Difference Supercell Approach, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Zhihao Lan, Wei E.I. Sha
Electrical and Computer Engineering Faculty Research & Creative Works
Topological photonic systems have been explored extensively due to the robust electromagnetic states they support. In this work, we propose a finite-difference supercell approach to analyze the topological property of photonic crystal (PC) structures. Meanwhile, the pseudospin polarized edge states at the interface of two PC structures with different topologies are studied. The direction of the energy flow is found to be determined by the helicity of the pseudospin polarization.
Source Reconstruction Method Based On Machine Learning Algorithms, He Ming Yao, Lijun Jiang, Wei E.I. Sha
Source Reconstruction Method Based On Machine Learning Algorithms, He Ming Yao, Lijun Jiang, Wei E.I. Sha
Electrical and Computer Engineering Faculty Research & Creative Works
This paper proposes a new source reconstruction method (SRM) based on deep learning. The conventional SRM usually requires oversampled measurements data to ensure higher accuracy. Thus, conventional SRM numerical system is usually highly singular. A deep convolutional neural network (ConvNet) is proposed to reconstruct the equivalent sources of the target to overcome difficulty. The deep ConvNet allows us to employ less data samples. Besides, the ill-conditioned numerical system can be effectively avoided. Numerical examples are presented to demonstrate the feasibility and accuracy of the proposed method. Its performance is also compared with the traditional neural network and interpolation method. Moreover, …
Fault Detection And Estimation For A Class Of Nonlinear Distributed Parameter Systems, Hasan Ferdowsi, Jia Cai, Sarangapani Jagannathan
Fault Detection And Estimation For A Class Of Nonlinear Distributed Parameter Systems, Hasan Ferdowsi, Jia Cai, Sarangapani Jagannathan
Electrical and Computer Engineering Faculty Research & Creative Works
This paper presents a new model-based fault detection and estimation framework for a class of multi-input and multi-output (MIMO) nonlinear distributed parameter systems (DPS) described by partial differential equations (PDE) with actuator and sensor faults. The fault functions cover both abrupt and incipient faults. A Luenberger type observer is used to monitor the health of the DPS as a detection observer on the basis of the nonlinear PDE representation of the system with measured output vector. By taking the difference between measured and estimated outputs from this observer, a residual signal is generated for fault detection. If the detection residual …
Effect Of Gate Voltage On The Photovoltaic Performance Of Gaas-Based Schottky Junction Solar Cells, Amirhossein Ghods, Vishal Saravade, Andrew Woode, Chuanle Zhou, Ian T. Ferguson
Effect Of Gate Voltage On The Photovoltaic Performance Of Gaas-Based Schottky Junction Solar Cells, Amirhossein Ghods, Vishal Saravade, Andrew Woode, Chuanle Zhou, Ian T. Ferguson
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, the effect of external gate voltage on GaAs-based metal-semiconductor (MS) Schottky solar cells is investigated. Subsequent changes in photovoltaic characteristic properties of the solar cells are extracted, reported and explained. Under positive gate voltages, the open-circuit voltage and short-circuit current density measured at collector are significantly increased due to the drift of holes from gate junction to the collector (forward bias condition of gate junction). However, there is slight increase in open-circuit voltage under reverse gate voltages, where only thermally generated electrons drift toward the collector junction. Moreover, negative gate voltage on insulated gate contact has resulted …
Novel And Efficient Parasitic Decoupling Network For Closely Coupled Antennas, Min Li, Lijun Jiang, Kwan Lawrence Yeung
Novel And Efficient Parasitic Decoupling Network For Closely Coupled Antennas, Min Li, Lijun Jiang, Kwan Lawrence Yeung
Electrical and Computer Engineering Faculty Research & Creative Works
A novel and efficient parasitic decoupling network (PDN) is proposed for closely coupled antennas in this paper, which provides a new perspective and approach to design DNs based on the parasitic decoupling concept. The PDN is composed of sections of transmission lines (TLs) and reactive components, allowing additional power-traveling paths. With the TL lengths and reactive component reactance being precisely determined, the traveling power from one antenna to another could cancel out the undesired power wave induced by mutual coupling, resulting in the high port isolation. The decoupling theory is rigorously derived with the design procedure of the PDN systematically …
A Phenomenological Model Of Non-Linear Loss In Ferrimagnetic Frequency-Selective Limiters, Anatoliy Boryssenko, Scott Gillette, Marina Koledintseva
A Phenomenological Model Of Non-Linear Loss In Ferrimagnetic Frequency-Selective Limiters, Anatoliy Boryssenko, Scott Gillette, Marina Koledintseva
Electrical and Computer Engineering Faculty Research & Creative Works
Operation of ferrimagnetic frequency-selective limiters (FSL) is based on non-linear absorption in magnetized ferrite films at RF/microwave power levels exceeding some threshold. A new phenomenological model of non-linear loss in a ferrite medium has been proposed, and it has been implemented in an efficient numerical algorithm for an FSL performance prediction.
Design And Fabrication Of Algaas-Based 1.8ev Schottky Solar Cell, Amirhossein Ghods, Vishal Saravade, Andrew Woode, Chuanle Zhou, Ian T. Ferguson
Design And Fabrication Of Algaas-Based 1.8ev Schottky Solar Cell, Amirhossein Ghods, Vishal Saravade, Andrew Woode, Chuanle Zhou, Ian T. Ferguson
Electrical and Computer Engineering Faculty Research & Creative Works
In this paper, Schottky junction solar cells fully based on Al0.3Ga0.7As with optical band gap energy of 1.8 eV are designed, fabricated, and characterized. In solar cells based on AlGaAs/GaAs heterostructure, AlGaAs is mostly used as window or electron barrier layer, while GaAs is used as active photon absorbing layer. This work is among the first reports of AlGaAs based Schottky solar cells. AlGaAs/GaAs heterojunction grown using molecular beam epitaxy (MBE) is used for fabrication of photovoltaic devices. Photovoltaic properties of solar cells are reported, along with experimental details of device fabrication and characterization. The optimized bandgap energy of 1.8eV …
Theoretical Analysis And Experimental Realization Of Highly Effective Acceptor Ionization In Gan Via Mg Co-Doped With 4d-Element (In), Zhiqiang Liu, Xiaoyan Yi, Junxi Wang, Ian Ferguson, Na Lu, Jinmin Li
Theoretical Analysis And Experimental Realization Of Highly Effective Acceptor Ionization In Gan Via Mg Co-Doped With 4d-Element (In), Zhiqiang Liu, Xiaoyan Yi, Junxi Wang, Ian Ferguson, Na Lu, Jinmin Li
Electrical and Computer Engineering Faculty Research & Creative Works
In this work, we clarify the underlying physics and the acceptor ionization process in the In-Mg co-doping GaN. The fundamental understandings are also applicable for other co-doping nitride systems. We show the effective acceptors ionization stems mainly from the band structure tuning effect of the 4d orbitals of In atoms. In addition, temperature dependent defect-related photoluminescence analysis was proposed to examine the energy position of Mg impurity levels, which is crucially important in the design for high p-doping. Finally, a hole concentration, which is nearly one order of magnitude higher than what is typically achievable by direct Mg-doping, was achieved.
Data-Driven Integral Reinforcement Learning For Continuous-Time Non-Zero-Sum Games, Yongliang Yang, Liming Wang, Hamidreza Modares, Dawei Ding, Yixin Yin, Donald C. Wunsch
Data-Driven Integral Reinforcement Learning For Continuous-Time Non-Zero-Sum Games, Yongliang Yang, Liming Wang, Hamidreza Modares, Dawei Ding, Yixin Yin, Donald C. Wunsch
Electrical and Computer Engineering Faculty Research & Creative Works
This paper develops an integral value iteration (VI) method to efficiently find online the Nash equilibrium solution of two-player non-zero-sum (NZS) differential games for linear systems with partially unknown dynamics. To guarantee the closed-loop stability about the Nash equilibrium, the explicit upper bound for the discounted factor is given. To show the efficacy of the presented online model-free solution, the integral VI method is compared with the model-based off-line policy iteration method. Moreover, the theoretical analysis of the integral VI algorithm in terms of three aspects, i.e., positive definiteness properties of the updated cost functions, the stability of the closed-loop …
Monitoring Of Cure State Through The Use Of Microwaves, David Judd, Frank Gramling, Reza Zoughi, Mohammad Tayeb Ahmad Ghasr
Monitoring Of Cure State Through The Use Of Microwaves, David Judd, Frank Gramling, Reza Zoughi, Mohammad Tayeb Ahmad Ghasr
Electrical and Computer Engineering Faculty Research & Creative Works
A method of manufacturing a tire is provided that includes curing the tire (10) in a curing press (12) and applying microwave energy at a given frequency band into the tire. The interaction between the microwave energy and the tire is monitored to obtain a complex reflection coefficient. A root-mean-squared error is calculated using the measured complex reflection coefficient and a reference reflection coefficient. The reference reflection coefficient is from a fully cured tire made from the same material as the tire. Continuous monitoring of the interaction takes place to obtain the complex reflection coefficient along …
Investigation Of The Optical Properties Of Insb Thin Films Grown On Gaas By Temperature-Dependent Spectroscopic Ellipsometry, Yuanlan Liang, Fangze Wang, Xuguang Luo, Qingxuan Li, Tao Lin, Ian T. Ferguson, Qingyi Yang, Lingyu Wan, Zhe Chuan Feng
Investigation Of The Optical Properties Of Insb Thin Films Grown On Gaas By Temperature-Dependent Spectroscopic Ellipsometry, Yuanlan Liang, Fangze Wang, Xuguang Luo, Qingxuan Li, Tao Lin, Ian T. Ferguson, Qingyi Yang, Lingyu Wan, Zhe Chuan Feng
Electrical and Computer Engineering Faculty Research & Creative Works
InSb thin films were grown on GaAs substrates by metal organic chemical vapor deposition (MOCVD) and investigated by temperature-dependent spectroscopic ellipsometry (TD-SE). The refractive index, extinction coefficient, and dielectric function of the InSb films were extracted. The variation of critical point energies (E 1 , E 1 +Δ 1 , E 2 , E1') related to the excited state transitions of InSb and the second energy derivatives of the dielectric function at different temperatures showed that the InSb thin film had high electrical and optical stability at the evaluated temperatures. TD-SE analysis revealed a temperature range suitable for the use …
The Decoupling Methods For Increasing The Isolation Between Two Antennas, Min Li, Lijun Jiang
The Decoupling Methods For Increasing The Isolation Between Two Antennas, Min Li, Lijun Jiang
Electrical and Computer Engineering Faculty Research & Creative Works
This paper presented the parasitic structure decoupling method and other related approaches to increase the isolation between two closely coupled antennas. The design parameters of the resultant decoupling structures based on the proposed methods can be precisely derived instead of fitted to achieve high antenna isolations. A two-element monopole array is employed as a benchmark to demonstrate the effectiveness of the proposed methods. The simulation results show that good impedance matching and high port isolation could be achieved simultaneously based on the proposed methods.
A 2d/Q-2d Subdomain Finite Element Method For Irregular Power/Ground Plate-Pair Analysis With Waveport Excitation, Ping Li, Li (Lijun) Jun Jiang, Yao Jiang Zhang, Shuai Xu, Hakan Bagci
A 2d/Q-2d Subdomain Finite Element Method For Irregular Power/Ground Plate-Pair Analysis With Waveport Excitation, Ping Li, Li (Lijun) Jun Jiang, Yao Jiang Zhang, Shuai Xu, Hakan Bagci
Electrical and Computer Engineering Faculty Research & Creative Works
The field distribution of a power/ground plane can be fully characterized by TMzmn modes, where the electric fields have both azimuthal and longitudinal components and the magnetic fields have only the azimuthal component. Thus, if the magnetic fields are defined to be the unknowns in the finite element method (FEM) used for the analysis of the power/ground plane structure, the analysis becomes a quasi-two dimensional (Q-2D) problem. Since the high-order modes are evanescent, they are tightly confined to the near region of the vias guarded by anti-pads; while in the regions sufficiently far from the anti-pads, only the fundamental mode …
In Situ Nmr Parameter Monitoring Systems And Methods For Measuring Ph And Temperature, Ming Huang, Lingyu Chi, Rex E. Gerald Ii, Jie Huang, Annalise R. Pfaff, Klaus Woelk
In Situ Nmr Parameter Monitoring Systems And Methods For Measuring Ph And Temperature, Ming Huang, Lingyu Chi, Rex E. Gerald Ii, Jie Huang, Annalise R. Pfaff, Klaus Woelk
Electrical and Computer Engineering Faculty Research & Creative Works
Devices and methods are provided for measuring temperatures and pHs of a sample in situ using NMR spectroscopy, and for sealing one or more ends of a capillary tube after a reference material has been added to the capillary tube, which is used in an in situ NMR temperature measurement device. A method for measuring a pH of a sample in situ using NMR spectroscopy includes providing an in situ NMR pH measurement device. This device includes a sample housing member configured to house a target sample, at least one pH sensor configured to exhibit an NMR spectral change due …
Solar Concentrators Manufacture And Automation, Ernst Kussul, Tetyana Baydyk, Alberto Escalante Estrada, Maria Tersa Rodriguez Gonzalez, Donald C. Wunsch
Solar Concentrators Manufacture And Automation, Ernst Kussul, Tetyana Baydyk, Alberto Escalante Estrada, Maria Tersa Rodriguez Gonzalez, Donald C. Wunsch
Electrical and Computer Engineering Faculty Research & Creative Works
Solar energy is one of the most promising types of renewable energy. Flat facet solar concentrators were proposed to decrease the cost of materials needed for production. They used small flat mirrors for approximation of parabolic dish surface. The first prototype of flat facet solar concentrators was made in Australia in 1982. Later various prototypes of flat facet solar concentrators were proposed. It was shown that the cost of materials for these prototypes is much lower than the material cost of conventional parabolic dish solar concentrators. To obtain the overall low cost of flat facet concentrators it is necessary to …
Prism-Based Dgtd With A Simplified Periodic Boundary Condition To Analyze Fss With D2n Symmetry In A Rectangular Array Under Normal Incidence, Wending Mai, Ping Li, Huaguang Bao, Xianjin Li, Lijun Jiang, Jun Hu, Douglas H. Werner
Prism-Based Dgtd With A Simplified Periodic Boundary Condition To Analyze Fss With D2n Symmetry In A Rectangular Array Under Normal Incidence, Wending Mai, Ping Li, Huaguang Bao, Xianjin Li, Lijun Jiang, Jun Hu, Douglas H. Werner
Electrical and Computer Engineering Faculty Research & Creative Works
In this letter, we develop a prism-based discontinuous Galerkin time-domain (DGTD) algorithm with simplified periodic boundary conditions (PBCs) to analyze infinite doubly periodic frequency selective surfaces (FSS). Most FSS structures contain patterned planar conductive layers and supporting dielectric layers. These layers are very thin compared to the wavelength. Therefore, general tetrahedral discretization of space will unnecessarily increase the number of mesh elements, as well as the number of unknowns. Instead, we propose using prismatic elements, which are more optimal for planar structures, resulting in less unknowns, less memory usage, and higher efficiency. The accuracy of the proposed prism based DGTD …
Ripple Canceling In Power Conversion Circuits, Pourya Shamsi, Mehdi Ferdowsi
Ripple Canceling In Power Conversion Circuits, Pourya Shamsi, Mehdi Ferdowsi
Electrical and Computer Engineering Faculty Research & Creative Works
A power circuit substantially canceling ripples at the source. The power circuit includes a switching circuit configured to control a power flow between an input and an output, a main storage element electrically connected in series with the switching circuit, and a resonant tank electrically coupled to the switching circuit and configured to compensate for switching ripples in the main storage element. Aspects of the invention can be applied to a converter circuit or to an inverter circuit.
Improving The Drive Current Of Algan/Gan Hemt Using External Strain Engineering, Wei Chih Cheng, Siqi Lei, Wenmao Li, Feng Zhao, Mansun Chan, Hongyu Yu
Improving The Drive Current Of Algan/Gan Hemt Using External Strain Engineering, Wei Chih Cheng, Siqi Lei, Wenmao Li, Feng Zhao, Mansun Chan, Hongyu Yu
Electrical and Computer Engineering Faculty Research & Creative Works
The concentration of the two-dimensional electron gas (2DEG) at the AlGaN/GaN heterojunction is dominated by the stress developed in AlGaN layer. In this work, the output performance of AlGaN/GaN high electron mobility transistors (HEMTs) was improved by depositing a stressed SiNx as a passivation layer, and the external strain applied onto AlGaN was measured using Raman spectroscopy. As a result, an improvement in on-state resistance and drive current of the device was attained due to the extra 2DEG concentration induced by the external strain. Also, to determine the strain-induced threshold-voltage shift, the stress distribution over the gate region was analyzed.
Generation Of Orbital Angular Momentum In 3d Photonic Crystals, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Wei E.I. Sha
Generation Of Orbital Angular Momentum In 3d Photonic Crystals, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Wei E.I. Sha
Electrical and Computer Engineering Faculty Research & Creative Works
An approach to producing electromagnetic (EM) waves carrying orbital angular momentum (OAM) by using three-dimensional (3D) photonic crystals (PCs) is proposed. By introducing a point defect in the PCs, a localized rotation mode is excited and then radiated out through a circular opening upon the defect. The radiated wave carries well-defined OAM. The lowest four OAM modes, i.e., OAM indices of ±1 and ±2, are successfully generated. The effectiveness of our approach is validated by both full-wave simulations and experiments.
A Compact Wideband Slot-Loop Directional Antenna For Marine Communication Applications, Lidong Chi, Yihong Qi, Zibin Weng, Wei Yu, Weihua Zhuang
A Compact Wideband Slot-Loop Directional Antenna For Marine Communication Applications, Lidong Chi, Yihong Qi, Zibin Weng, Wei Yu, Weihua Zhuang
Electrical and Computer Engineering Faculty Research & Creative Works
A compact wideband high gain directional antenna is proposed in this paper for marine communications. The antenna consists of a back plane (reflector), a slot-loop antenna (driven element), and a director of rod. Based on the current distribution, the slot-loop antenna is equivalent to an array of three linear current dipoles. The dipole acts as an element of the director, which provides a highly efficient director for slot-loop antenna according to theoretical analysis. Both the impedance bandwidth and the 1 dB gain bandwidth are 45% covering 1.7-2.7 GHz in this design. A gain of 11.2 to 12.2 dBi is obtained …
Quasi-Continuous Metasurfaces For Orbital Angular Momentum Generation, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Wei E.I. Sha
Quasi-Continuous Metasurfaces For Orbital Angular Momentum Generation, Menglin L.N. Chen, Li (Lijun) Jun Jiang, Wei E.I. Sha
Electrical and Computer Engineering Faculty Research & Creative Works
A quasi-continuous composite perfect electric conductor-perfect magnetic conductor metasurface and a systematic metasurface design process are proposed for the orbital angular momentum (OAM) generation. The metasurfaces reflect the incident left circularly polarized (LCP)/right circularly polarized (RCP) plane wave to RCP/LCP vortex beams carrying OAM at normal or oblique direction. Unlike conventional metasurfaces that are composed of discrete scatterers, the scatterers on the proposed metasurface form a quasi-continuous pattern. The patterning of the metasurface is calculated through grating vectors, and no optimization of single scatterer is required. Furthermore, the distortions from local-response discontinuity of discrete scatterers are avoided. This letter provides …