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In this article, numerical result obtained using two different commercially available electromagnetic (EM) codes based on an integral equation method are presented. One of the methods solves the integral equation by the method of moments (MoM) using higher order basis functions (the commercially available parallel software named TIDES), and the other one solves the integral equation by MoM with a multilevel fast multipole algorithm (MLFMA) incorporating the RWG basis functions (the commercially available software FEKO). Numerical results indicate that the integral equation solver with higher order basis functions occupies less than 40% of the RAM and the execution time is significantly less when compared with that of using the RWG basis functions along with MLFMA. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1219–1225, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24271 [ABSTRACT FROM AUTHOR]

A novel bandpass filter with two dual-mode cavities based on the substrate integrated waveguide (SIW) is presented. By making use of the inductive discontinuities in an SIW cavity, two degenerate modes can be excited. Due to the phase difference of the two modes in each cavity, two transmission zeros on each side of the passband are created, so the out-of-band rejection of the filter is significantly improved. An SIW dual-mode filter with a center frequency of 12 GHz has been fabricated and measured. The experimental results agree well with the simulation results. [ABSTRACT FROM AUTHOR]

This paper presents a novel dual-band banpass filter using microstrip open-loop resonators. A new microstrip unit of dual-band bandpass filter is introduced, which can be used as unit element of duan-band filter design. The two open-loop resonators are treated as passband resonator and stopband resonator in analysis, respectively. A five-pole C-band dual-band bandpsss filter has been designed and fabricated. The measured results show a good agreement with the simulated results. [ABSTRACT FROM AUTHOR]

Electromagnetic band-gap (EBG) structures exhibit unique electromagnetic properties that have led to a wide range of applications to the antenna and propagation fields. This paper investigates the performance of a waveguide end-slot phased array (WESPA) antenna integrated with mushroom-like EBG structures. The mushroom-like EBG structure has the advantage of compactness and offers the capability to block the surface wave coupling of the phased array, which provides a possible solution to the "blind spots" problem of the WESPA. Some novel and efficient EBG array configurations are proposed, and an infinite phased array and a finite phased array of 3 × 9 slot elements are analyzed. The tradeoffs and design considerations of EBG structures are discussed to obtain optimum performance. [ABSTRACT FROM AUTHOR]

A simple and systematic derivation of strongly well-posed perfectly matched layer (PML) in cylindrical and spherical coordinates is presented. The unsplit-field PML formulations are expressed in terms of the complex coordinate stretching approach which was originally proposed for split-field PML. The well-posed PML formulations include the symmetric hyperbolic system besides some lower order terms which do not affect the well-posedness of the system. Numerical simulations validate the accuracy and efficiency of the unsplit-field PML. [ABSTRACT FROM AUTHOR]

This paper presents the generalized constraint conditions for an arbitrary lossless multiport network in partitioned matrix forms, which involve the constraints at magnitudes, phases and determinant of the scattering matrix. The results show that some special properties of a lossless two-port network, such as quasi-reciprocity, quasi-symmetry, and π-convergence of characteristic phases, can be generalized to a lossless N-port network in partitioned matrix forms. Some examples of lossless networks are given to illustrate the application and validity of the proposed approach in this paper. [ABSTRACT FROM AUTHOR]

The conditions for perfect absorption under oblique incidence in a single-layer homogeneous absorber backed by a perfectly conducting plate are derived in this article. The cases corresponding to the two types of polarization of the incidence-wave, perpendicular polarization (TE) and parallel polarization (TM), are discussed, respectively. Some conclusions and curves are given. [ABSTRACT FROM AUTHOR]

Electromagnetic bandgap (EBG) structures consisting of fractal high impedance topologies and effective bridges are proposed and employed for ultra-wideband (UWB) ground bounce noise (GBN) suppression in power and ground plane pairs. These structures have shown good performance. For the first design utilizing fractal high impedance topology with one iteration and meander lines, it provides -49 dB noise suppression from 202 MHz to 20 GHz. Both simulated and measured results are presented to verify the performance. Furthermore, the GBN suppression behaviors of topologies with different iterations have been studied, and the impact of the power plane with the first design on the signal integrity has also been investigated. [ABSTRACT FROM AUTHOR]

The propagation characteristics of the electromagnetic wave incident from a linear conventional medium (RHM) into a nonlinear left-handed medium (LHM) and the Goos-Hänchen shift of total reflection at the interface are derived in this paper. The dependence of the lateral shift on the incident angle and incident field intensity is analyzed. It is found that the incident field intensity plays an important role in the propagation of the electromagnetic wave. If the incident field intensity is larger than the critical field intensity, total reflection condition is not satisfied and the incident beam penetrates into the nonlinear materials partly. Proposed nonlinear dielectric waveguide is of great value because it can not only regulate the lateral shift but also implement control over the incident field intensity. [ABSTRACT FROM AUTHOR]

A method of improving the gain of circular waveguide array antenna using one-dimensional (1-D) electromagnetic band-gap (EBG) structure is proposed in this paper. The detailed analysis is made to study the radiation characteristics of circular waveguide antenna and its array with 1-D EBG structure. The simulation and experimental results show an about 7 dB addition in the antenna gain in compared with the conventional antenna, which proves that the radiation characteristics of antenna array using EBG structure are improved. [ABSTRACT FROM AUTHOR]

In this paper, the concept of "the optimum virtual topology" for MPI based Parallel FDTD is firstly presented. The Parallel Conformal FDTD code developed by our group earlier was run on a PC cluster with high performance to analyze a new type of PBG microstrip filter structure and a new type of base station antenna. Taking them as examples, the influence of virtual topology schemes on parallel performance of Parallel FDTD is studied in detail. Finally the general rules are presented on how to obtain the highest efficiency of Parallel FDTD algorithm by optimizing MPI virtual topology. [ABSTRACT FROM AUTHOR]

A method of raising the front to back (F/B) ratio on the pattern for the slot array antenna of rectangular waveguide by using electromagnetic band-gap (EBG) structure as a high-impedance ground plane is studied in this paper. The benefits of using such an EBG structure are related to the suppression of surface waves excited by the slots of waveguide. In agreement with the expected results, the simulation and experimental radiation patterns show that the EBG structure can increase the front radiation, decrease the back radiation and improve the gain of slot array antenna. [ABSTRACT FROM AUTHOR]

This paper presents a new set of formulas to compute the field distribution near an electrically large conductor modeled by non-uniforrn rational B-spline (NURBS) surfaces using physical optics (PO) method. Stationary phase method is applied to calculate the PO integral on the rational Bezier Surface. Results obtained by these formulas and by traditional PO method using triangle-modeling technique agree well, which show the accuracy and efficiency of this method. [ABSTRACT FROM AUTHOR]

A large scale low-profile traveling-wave narrow-wall slotted waveguide array with 2160 slots is analyzed by parallel method of moments (MoM) out-of-core solver based on the higher order basis functions (HOBs). Its accuracy is validated through comparison with the finite element method (FEM) adopted in the commercial software Ansoft HFSS. An out-of-core two-dimensional block-cyclic distribution scheme for the large dense full matrix filling and an out-of-core LU (lower/upper) decomposition matrix equation solver are utilized under the message passing interface (MPI). Numerical results are shown to demonstrate the memory cost effectiveness, time efficiency of the proposed method and its applicability. The method presented in this paper is able to solve challenging realistic problems in large scale. [ABSTRACT FROM AUTHOR]

This paper presents a novel synthesis method for asymmetric dual-passband microwave filters. The proposed method employs frequency transformation technique to determine the locations of poles and zeros of a desired filter. This method can be used to design dual-passband filters with prescribed passbands directly without any need of optimization process. Then an eight-pole asymmetric dual-passband filter is designed efficiently to validate the transformation technique. This universal method will be useful for the design of various high performance microwave dual-passband filters in the communication systems. [ABSTRACT FROM AUTHOR]