Efficient Full-wave Method Research Articles

An Efficient Full-Wave Method for Analyzing the Radiation Pattern of an Antenna Enclosed by an Axisymmetric Radome

This article proposes an efficient full-wave method to analyze the radiation pattern of an antenna in the presence of a multilayer axisymmetric radome. In this method, first, the field distribution on the antenna aperture is replaced with the respective equivalent currents to compute the incident electromagnetic field on the inner surface of the radome. The radome is then modeled with a cascaded network of two-port devices and generalized transmission lines based on the theory of surface equivalence and the method of moments. The cascaded network is used to relate the tangential components of the electromagnetic field at the inner surface of the radome to their counterparts at the outer surface of the radome which, in turn, are used to obtain the respective equivalent currents. Finally, these currents are used to determine the radiation pattern of the antenna in the presence of the radome. The efficiency of the proposed method is demonstrated by comparing the simulation results of several case studies with those obtained by the rival theoretical models in the literature or computed by commercial numerical codes.

Characteristics of HTS inverted circular patches on anisotropic substrates

In this study, an efficient full-wave method is developed for characterizing the resonant frequencies, bandwidths, and quality factors of an inverted circular superconducting patch antenna. Our technique is based on the Galerkin procedure in the Hankel transform domain (HTD) combined with the complex resistive boundary conditions. With the use of suitable Green’s functions in the HTD, the analysis is performed for the case where the superconducting circular patches is printed on an anisotropic substrate. The numerical results obtained using this approach are compared with the experimental results. These comparisons were very good, which proves the correctness and the validity of the method. It is found that the optical properties combined with optimally-chosen structural parameters of anisotropic materials can maintain control of the resonant frequency and exhibit wider bandwidth characteristics.

Signal integrity analysis for high-speed circuit PCB interconnection with an efficient full wave method

In this article, a partial equivalent element circuit (PEEC) method with Rao-Wilton-Glisson (RWG) basis functions and discrete complex image (DCI) is proposed. Circuit model and its formula are derived. With the proposed RWG-DCI-PEEC method, signal integrity (SI) simulations of high speed differential traces on PCB are carried out in time domain, including response of time domain reflectometry (TDR) and eye diagram of worst case analysis, and are compared with experimental measurements and other commercial softwares. The correctness and effectiveness of our proposed method are verified. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.

Efficient Full-Wave Method of Moments Analysis and Design Methodology for Radial Line Planar Antennas

An efficient full-wave MoM analysis and a design methodology for radial line planar antennas (RLPA) is presented. The feeding network of the antenna is solved by using the appropriate Green's function defined for the problem. Filling of the Z-matrices is considerably simplified due to the analytical formulation of the MoM. Also, assumptions made on the minimum size of the coupling neighborhood for the feeding conductive probes in the radial line enabled significant time reduction of the time spent on the matrix inversion. Moreover, exploration of the RLPA symmetries leads to several improvements in the overall performance. The MoM results of the feeding network are combined with the results of the radiating elements for obtaining the performance of the feeding network under load conditions. It is shown that the radial position of the radiating elements in the RLPA resemble an equilateral triangular array grid. This observation enabled to perform the analysis of the array external mutual coupling effect using the equivalent “unit-cell” concept derived from an infinite phased array analysis. Comparison of the MoM results of the feeding network to CST commercial software show significant computational timesavings and the results are found to be in a good agreement.

Efficient full‐wave analysis method of leaky‐wave modes in periodically loaded dielectric waveguides with application to backward‐to‐forward frequency‐scannable antennas and metamaterials

AbstractThis work presents a novel and efficient full‐wave method specifically conceived for the modal analysis of periodic planar metallizations printed on the open side of a dielectric rectangular waveguide. This particular type of structures can be used to conceive interesting backward‐to‐forward frequency‐scanning periodic leaky‐wave antennas, including leaky‐wave antennas based on the composite right–left‐handed transmission line concept (metamaterial). For the analysis, the spectral‐domain Green's functions are obtained by expanding the electromagnetic fields as a double summation of Floquet and parallel‐plate modes. An original and simple coupled equivalent circuit is used to deal with the multilayered stratification arrangement and the top radiation boundary. The method of moments (MoM) is applied to solve the corresponding EFIE/MFIE, and an original iterative technique is used to search for the complex leaky‐wave mode zeros of the determinant of the MoM matrix. All the expressions are in closed form, while keeping its full‐wave nature. The convergence and the accuracy of the method are both studied. Once the backward leaky‐waves are found, some interesting phenomena are examined, such as backward‐to‐forward beam scanning, appearance of bandgaps, mode coupling, multi‐space‐harmonic radiation, and antenna aperture illumination control. By studying a practical antenna and by comparing with previously published methods, it is shown the importance of a full‐wave analysis tool that can take into account all the aforementioned effects. Copyright © 2006 John Wiley & Sons, Ltd.

An efficient full-wave method for analysis of dielectric resonators possessing separable geometries immersed in inhomogeneous environments

In this paper, dielectric resonators possessing separable-coordinate geometries immersed in planarly-inhomogeneous media are analyzed using a volume electric-field integral-equation (IE)/Galerkin's technique. A three-dimensional complete entire-domain basis function set is utilized in numerically solving the IE. It is shown that a few terms of one physically significant subset of basis functions are usually sufficient for the accurate determination of complex resonant frequencies of cylindrical and rectangular resonators immersed in homogeneous and planarly inhomogeneous environments. The results using a few basis functions show good agreement with the previous literature, and new results are presented for some rectangular resonator geometries.

A microstrip‐coupled slot‐loop antenna for integrated receivers in the millimeter‐wave band

A square-loop slot antenna, printed at the back surface of an extended hemispherical lens, is examined as a candidate for millimeter-wave (mm-wave) integrated-circuit Schottky-diode mixers. The loop slot is etched in a microwave substrate, and coupled to a microstrip line section printed on the other side of the substrate. A Schottky barrier diode shunted to ground is the mixing device. The input impedance of the antenna has been optimized to conjugate match the Schottky diode. To design and optimize the antenna, an efficient full-wave method of moments (MoM) technique, which solves the mixed potential integral equation (MPIE) in the stratified medium, has been developed. Patterns have been computed using the physical optics approximation and diffraction theory. The proposed configuration shows very wideband performance. Simulation results compare well with measurements. The proposed configuration is suitable to be scaled down for operation in the submillimeter-wave (submm-wave) band. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 18: 91–95, 1998.

Full wave analysis of a 3D source near strips in a multilayer region

A rigorous and efficient full wave method to analyse the near field of a 3D source near conductive strips located in a multilayered region is presented. The excitation field by a 3D source is expanded into summation of plane waves and rotated to a new coordinated system to use the plane wave transmission formulation in multilayered media. The moment method is used to calculate the current induced on the strips by these plane waves. Only one matrix inverse is needed for all incident plane waves with the same propagation constant along the strip axis, thus the total computation time is greatly reduced. The accuracy of the proposed method is verified by comparison with UTD in free space.

Current distribution in superconducting thin-film strips

A closed-form expression is presented for the current distribution in an isolated strip made from a superconducting thin film with thickness less than a few penetration depths. This equation gives a good approximation within certain limits for the resistance and inductance per unit length of superconducting striplines and microstrip lines. Both the ac resistance of an isolated superconducting strip and the resistance per unit length of a superconducting stripline calculated using this closed-form expression agree well with the numerical results generated by the modified Weeks' method. The possibility of using this expression along with the integral equation method to develop an efficient full-wave method for analyzing superconducting planar transmission lines is discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>