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The computation of impedance matrix for layered structures is time-consuming because each element requires the evaluation of quadruple integrals. To increase the efficiency, we propose a technique referred to as the fast matrix generation. In this method, conventional and rigorous numerical methods are still used for generating the impedance matrix elements that are associated with the near-field interactions, whereas a more efficient scheme is employed where the separation distance between basis and testing functions exceeds a threshold value. A significant saving in computation time, sometimes over 90%, can be achieved via the application of this approach, as is demonstrated by numerical results for a number of typical microwave circuits. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 204–213, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24015 [ABSTRACT FROM AUTHOR]

In this paper, we present an efficient electromagnetic analysis of planar microstrip structures, called the characteristic basis function method (CBFM). In this method, the original problem geometry is segmented into smaller regions called sections, and high-level basis functions are generated to represent the electromagnetic characteristics of these sections. These basis functions are referred to as the characteristic basis functions (CBFs), and their use leads to a reduced matrix equation. Since the method only requires the solution of small-size matrix equations, associated with isolated domains, the computational burden is relieved, and an acceleration of the solve time is achieved. The efficiency of this method is demonstrated via several examples, including a filter and an amplifier circuit. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 444–448, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11085 [ABSTRACT FROM AUTHOR]

This Letter presents a simple and efficient approach for preconditioning a large dense system of linear equations arising in the method-of-moments (MoM) solution of electromagnetic (EM) problems. A two-step process is presented in which the condition number of the matrix is first improved by equilibration, and then further enhanced by preconditioning. The convergence properties of two frequently used iterative solvers, namely, the conjugate-gradient normal (CGNR) and the generalized minimal residual (GMRES) methods, have been studied with the use of the proposed technique, and the efficacy of the method has been compared with that of the direct LU factorization. The Letter demonstrates that the proposed technique helps improve the computational efficiency of the iterative solvers considerably, not only for MoM matrices associated with electrically large geometries, but also for poorly conditioned matrices with a relatively small rank. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 196–200, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10274 [ABSTRACT FROM AUTHOR]

This article introduces a simple and efficient technique for generating the initial guess for iterative solutions of a large dense system of linear equations arising in the method-of-moments (MoM) formulation of electromagnetic (EM) problems. The proposed approach is based on an extrapolation of the solution vector from those generated at previous frequencies. The extrapolated solution is further refined, if required, by using the conjugate gradient (CG) technique. Questions regarding the accuracy of the solution, as well as its dependency on the stopping criterion and the frequency step size, have been investigated for a large class of EM problems, and representative results are presented. The superiority of the present technique over existing approaches for generating the initial estimate of the solution is demonstrated. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 74–78, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10243 [ABSTRACT FROM AUTHOR]

We isolated and characterized 13 polymorphic microsatellite primers from Perilla frutescens Brit. var. frutescens by using a modified method that involves one-way PCR amplification with single primer prior to enrichment with an 'oligo hook'. The efficiency of this procedure for isolating unique microsatellite sequences was approximately 77%. The number of alleles per microsatellite locus ranged from three to 10 with an average of 6.5 alleles per locus while fragment size varied from 156 to 298 bp. The observed and expected heterozygosities ranged from 0.52 to 0.86 and 0.52 to 0.89, respectively. These newly isolated microsatellite markers are expected to provide valuable resources for different genetic studies currently underway in our Perilla genome research program. [ABSTRACT FROM AUTHOR]