Derivation of the closed-form Green's functions has eliminated the computationally expensive evaluation of the Sommerfeld integrals to obtain the Green's functions in the spatial domain. Therefore, using the closed-form Green's functions in conjunction with the method of moments (MoM) has unproved the computational efficiency of the technique significantly. Further improvement can be achieved on the calculation of the matrix elements involved in the MoM, usually double integrals for planar geometries, by eliminating the numerical integration. The contribution of this paper is to present the analytical evaluation of the matrix elements when the closed-form Green's functions are used, and to demonstrate the amount of improvement in computation time. © 1996 IEEE

To make three-dimensional (3-D) on-chip interconnect inductance extraction tractable, it is necessary to ignore parasitic couplings without compromising critical properties of the interconnect system. It is demonstrated that simply discarding faraway mutual inductance couplings can lead to an unstable approximate inductance matrix. In this paper, we describe an equipotential shell methodology, which generates a partial inductance matrix that is sparse yet stable and symmetric. We prove the positive definiteness of the resulting approximate inductance matrix when the equipotential shells are properly defined. Importantly, the equipotential shell approach also provably preserves the inductance of loops if they are enclosed entirely within the shells of their segments. Methods for sizing the shells to control the accuracy are presented. To demonstrate the overall efficacy for on-chip extraction, ellipsoid shells, which are a special case of the general equipotential shell approach, are presented and demonstrated for both on-chip and system-level extraction examples.

The shift-truncate potential method was introduced as an approach to sparsify the partial inductance matrix while maintaining the stability and symmetry. This was accomplished with the use of spherical return shells around point-like current segments. In this paper we propose the use of filament current distributions for the same purpose. Ellipsoidal shells are introduced to model the equipotential surfaces for filament currents. Importantly, we prove that the positive definiteness of the resulting sparse partial inductance matrix is preserved for this and all other potential-shell models when the compensating currents are placed on equipotential surfaces of the original current distribution. The utility and efficiency of this ellipsoidal shell partial inductance approximation are demonstrated for both on-chip and system-level extraction examples.

Dual-frequency operation of antennas has become a necessity for many applications in recent wireless communication systems, such as GPS, GSM services operating at two different frequency bands, and services of PCS and IMT-2000 applications. Although there are various techniques to achieve dual-band operation from various types of microstrip antennas, there is no efficient design tool that has been incorporated with a suitable optimization algorithm. In this paper, the cavity-model based simulation tool along with the genetic optimization algorithm is presented for the design of dual-band microstrip antennas, using multiple slots in the patch or multiple shorting strips between the patch and the ground plane. Since this approach is based on the cavity model, the multiport approach is efficiently employed to analyze the effects of the slots and shorting strips on the input impedance. Then, the optimization of the positions of slots and shorting strips is performed via a genetic optimization algorithm, to achieve an acceptable antenna operation over the desired frequency bands. The antennas designed by this efficient design procedure were realized experimentally, and the results are compared. In addition, these results are also compared to the results obtained by the commercial electromagnetic simulation tool, the FEM-based software HFSS by ANSOFT

Cataloged from PDF version of article.Derivation of the closed-form Green’s functions\ud and analytical evaluation of the method of moments (MOM)\ud matrix entries have improved the computational efficiency of\ud the significantly in the analysis of printed geometries. With this\ud background in mind, an extension of this efficient numerical technique\ud is to incorporate an optimization algorithm and to assess its\ud potential as a computer-aided design (CAD) tool. Therefore, we\ud have employed the Gradient search and Genetic algorithms, in\ud conjunction with the electromagnetic (EM) simulation technique,\ud to a number of representative examples of interest

No abstract

No abstract

No abstract