A memory saving vector fast multipole algorithm for solving the augmented EFIE

An augmented EFIE (A-EFIE)[9], [10] has been proposed to separate the contributions of the vector potential and the scalar potential for avoiding the imbalance at low frequencies. The corresponding low frequency fast multipole algorithm (LFFMA) [11] was also developed for solving the A-EFIE. Instead of the factorization of the scalar Green's function by using scalar addition theorem in the LF-FMA, we adopt the vector addition theorem for the factorization of the dyadic Green's function to realize memory savings. We are to develop a vector fast multipole algorithm for solving the A-EFIE. © 2010 IEEE.published_or_final_versionThe URSI International Symposium on Electromagnetic Theory (EMTS 2010), Berlin, Germany, 16-19 August 2010. In Proceedings of the URSI International Symposium on Electromagnetic Theory, 2010, p. 134-13

Finite-width feed and load models

We demonstrate a new method of applying the feed model for the method of moments (MoM) formulation for the electric field integral equation (EFIE). The model is based around a previously reported magnetic ribbon current model which is accurate and allows for a finite width of the feed port. However, with proper approximations, one can reduce the formulation such that the magnetic field operator can be removed in order to simplify computations arising from the curl of the dyadic Green's function and its singularities. We show here that the new feed model can also be used to model a lumped element. © 1963-2012 IEEE.published_or_final_versio

Design of dual-band slotted patch hybrid couplers based on PSO algorithm

A planar 3 dB patch hybrid coupler using cross and circular-shape slots is presented for a dual-band application. By inductively loading a pair of cross slots and four circular holes on a square patch, the matching and isolation performance of the miniaturized patch hybrid coupler is improved. In addition, the open-circuited shunt stubs are further installed at four ports to realize two operating bands. Since the slotted patch resonator cannot be characterized by the closed-form transmission line theory, the particle swarm optimization (PSO) algorithm is constructed and integrated with a full-wave solver to determine the variable parameters of the proposed structure. Finally, a prototype dual-band coupler operating at 915 MHz and 1575 MHz is designed and fabricated. Measured results show a good agreement with those obtained from simulation. © 2011 VSP.postprin

Log-Periodic Dipole Array Antenna as Chipless RFID Tag

postprin

Coexistence of pseudospin- and valley-Hall-like edge states in a photonic crystal with C3v symmetry

We demonstrate the coexistence of pseudospin- and valley-Hall-like edge states in a photonic crystal with C 3 v symmetry, which is composed of three interlacing triangular sublattices with the same lattice constants. By tuning the geometry of the sublattices, three complete photonic band gaps with nontrivial topology can be created, one of which is due to the band inversion associated with the pseudospin degree of freedom at the Γ point and the other two due to the gapping out of Dirac cones associated with the valley degree of freedom at the K , K ′ points. The system can support triband pseudospin- and valley-momentum locking edge states at properly designed domain-wall interfaces. Furthermore, to demonstrate the novel interplay of the two kinds of edge states in a single configuration, we design a four-channel system, where the unidirectional routing of electromagnetic waves against sharp bends between two routes can be selectively controlled by the pseudospin and valley degrees of freedom. Our work combines the pseudospin and valley degrees of freedom in a single configuration and may provide more flexibility in manipulating electromagnetic waves with promising potential for multiband and multifunctional applications

Preemptive regression test scheduling strategies: a new testing approach to thriving on the volatile service environments

A workflow-based web service may use ultra-late binding to invoke external web services to concretize its implementation at run time. Nonetheless, such external services or the availability of recently used external services may evolve without prior notification, dynamically triggering the workflow-based service to bind to new replacement external services to continue the current execution. Any integration mismatch may cause a failure. In this paper, we propose Preemptive Regression Testing (PRT), a novel testing approach that addresses this adaptive issue. Whenever such a late-change on the service under regression test is detected, PRT preempts the currently executed regression test suite, searches for additional test cases as fixes, runs these fixes, and then resumes the execution of the regression test suite from the preemption point. © 2012 IEEE |postprin

Generalized modal expansion of electromagnetic field in 2-D bounded and unbounded media

A generalized modal expansion theory is presented to investigate and illustrate the physics of wave-matter interaction within arbitrary two-dimensional (2-D) bounded and unbounded electromagnetic problems. We start with the bounded case where the field excited by any sources is expanded with a complete set of biorthogonal eigenmodes. In regard to non-Hermitian or nonreciprocal problems, an auxiliary system is constructed to seek for the modal-expansion solution. We arrive at the unbounded case when the boundary tends to infinity or is replaced by the perfectly matched layer (PML). Modes are approximately categorized into two types: trapped modes and radiation modes, which respond differently to environment variations. When coupled with the source, these modes contribute to the modal-expansion solution with different weights, which leads to a reduced modal representation of the excited field in some geometries. © 2002-2011 IEEE.published_or_final_versio

Solving multi-scale low frequency electromagnetic problems

In this paper, we will discuss two methods to tackle the low-frequency, multi-scale electromagnetics problem. First we will discuss the augmented electric field integral equation (AEFIE), and then, we will discuss the equivalence principle algorithm (EPA). The AEFIE allows the solution of such problems without the need to perform a loop search of a complex structure. The EPA allows the separation of circuit physics from wave physics in a multiscale problem. Hybridization of these two methods will be discussed.published_or_final_versionThe 4th European Conference on Antennas and Propagation (EuCAP) 2010, Barcelona, Spain, 12-16 April 2010. In Proceedings of the 4th EuCAP, 2010, p. 1-

DeformSyncNet: Deformation Transfer via Synchronized Shape Deformation Spaces

Shape deformation is an important component in any geometry processing toolbox. The goal is to enable intuitive deformations of single or multiple shapes or to transfer example deformations to new shapes while preserving the plausibility of the deformed shape(s). Existing approaches assume access to point-level or part-level correspondence or establish them in a preprocessing phase, thus limiting the scope and generality of such approaches. We propose DeformSyncNet, a new approach that allows consistent and synchronized shape deformations without requiring explicit correspondence information. Technically, we achieve this by encoding deformations into a class-specific idealized latent space while decoding them into an individual, model-specific linear deformation action space, operating directly in 3D. The underlying encoding and decoding are performed by specialized (jointly trained) neural networks. By design, the inductive bias of our networks results in a deformation space with several desirable properties, such as path invariance across different deformation pathways, which are then also approximately preserved in real space. We qualitatively and quantitatively evaluate our framework against multiple alternative approaches and demonstrate improved performance

Generation of Orbital Angular Momentum by a Point Defect in Photonic Crystals

As an attractive degree of freedom in electromagnetic (EM) waves, the orbital angular momentum (OAM) enables infinite communication channels for both classical and quantum communications. The exploration of OAM generation inspires various designs involving spiral phase plates, antenna arrays, metasurfaces, and computer-generated holograms. In this work, we theoretically and experimentally demonstrate an approach to producing OAM carrying EM waves by a point defect in three-dimensional (3D) photonic crystals (PCs). Simultaneous excitation of two vibrational-defect states with an elaborately engineered phase retardation generates a rotational state carrying OAM. Through converting guided waves in a line defect to localized waves in a point defect and then to radiated vortex waves in free space, the lowest four OAM-mode emitters, i.e., OAM indices of ± 1 and ± 2 , are successfully realized. This work offers a physical mechanism to generate OAM by PCs, especially when the OAM generation is to be integrated with other designs