摘要:

AbstractThe Letter presents a method for the rigorous analysis of the microstrip Yagi antenna. Using the mixed potential integral equation (MPIE) for patch antennas, the FFT algorithm and the biconjugate gradient iterative method, the solution for the unknown current distribution on the patch is obtained in an efficient manner without requiring the storage of large matrices that typically arise in moment‐method computations. Consequently, the scheme can deal with patches of arbitrary shapes and can handle a very large number of unknowns. Numerical results of input impedance and radiation patterns are compared with measured result

ISSN:0895-2477    

DOI:10.1002/mop.4650080302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe optical bistability in a nonlinear fiber‐optic LP01mode converter by a reflective fiber grating is theoretically investigated. Both the transmissive and reflective properties of the device are analyzed. The output‐versus‐input function of the device exhibits the optical bistability property. The switching power and the bistable hysteresis are also discussed. In addition, a comparison between the nonlinearly reflective mode converter (LP01↔ LP02) and the nonlinear fiber Bragg grating reflector (i.e., LP01and counterpropagating LP01modes) is also presented. Our results show that the former has much lower switching power than the

ISSN:0895-2477    

DOI:10.1002/mop.4650080303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe article demonstrates that a Method‐of‐Moments solution for large, smooth, two‐dimensional scatterers, requiring matrices that are several hundreds to several thousands in size, can be constructed efficiently by using a combination of transformations based upon FFT and partial QR decomposition of off‐diagonal blocks. The primary contribution of the article is to demonstrate that these techniques, applied in tandem, can typically reduce the active RAM requirements by a factor of 60‐100 for moderately large problems, and by as much as 225 (estimated) for matrix sizes around 100,000. It is also estimated that an effective flop rate of about 8‐35 N2In N to 0.01N3can be achieved via this transformation. The reduction factors for RAM requirements and the accuracy of the solution are demonstrated for the problem of a 2D elliptic cylinder with a large aspect ratio, requiring matrix sizes u

ISSN:0895-2477    

DOI:10.1002/mop.4650080304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this article, a fast and novel method is proposed to determine accurately and efficiently the singularity due to the surface wave as found in the electric field integral equation. The method involves a simple reorganization of the classical expressions for both the transverse electric (DTE) and the transverse magnetic surface wave modes (DTM) into some piecewise linear forms suitable for the Newton‐Raphson algorithm. Extensive numerical comparison is made with some of the classical methods used for pole extraction. The numerical results, as presented, confirm efficiency and fast quadratic convergenc

ISSN:0895-2477    

DOI:10.1002/mop.4650080305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA new configuration of a cylindrical microstrip line mounted inside a ground cylinder is studied. Quasistatic expressions of the effective dielectric constant and characteristic impedance for such a microstrip line are derived. Numerical results are also calculated and compared with those obtained for a corresponding planar microstrip line. It is also found that the quasistatic characteristics for such a microstrip line with various curvatures are in contrast to the case of a cylindrical microstrip line mounted on a ground cylinder.

ISSN:0895-2477    

DOI:10.1002/mop.4650080306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe nonorthogonal finite‐difference‐time‐domain method is applied to the analysis of structures in a square coaxial waveguide to demonstrate the influence of the mesh on the results. The analysis presented provides insight on how best to discretize the computational domain when modeling discontinuities with this method. Three structures, described as 90°, 120°, and 170° bends, are used as examples in our analysis. A comparison is made with results obtained using the FEM method for the 90° bend. The comparison shows good agreement between these two t

ISSN:0895-2477    

DOI:10.1002/mop.4650080307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA planar 3‐dB quadrature coupler in the form of an eight‐port elliptical disc is investigated. The hybrid consists of additional arbitrarily loaded reactive stubs and impedance steps for tuning purposes. A contour‐integral method of analysis is used to obtain the electric parameters of the stru

ISSN:0895-2477    

DOI:10.1002/mop.4650080308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractReduction of the surface‐wave excitation is achieved by placing parasitic elements next to the radiating edges of a rectangular microstrip antenna. A new experimental technique is introduced to measure the effect of the parasitic strips in reducing the surface‐wave excitat

ISSN:0895-2477    

DOI:10.1002/mop.4650080309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe high computational load associated with multidimensional high‐resolution algorithms is overcome by using only 1D LP techniques. The 3D backscattered field is approximated by three 1D AR models that are solved in succession for the down‐range, horizontal cross‐range, and vertical cross‐range positions of the scattering centers of a

ISSN:0895-2477    

DOI:10.1002/mop.4650080310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA modified approach for computing the effective permittivity of a dielectric mixture has been applied to obtain the attenuation and phase shift of both horizontally and vertically polarized electromagnetic waves in the rain medium. This approach takes into consideration the distributions in raindrop sizes, shapes, and depolarization factors. The computed results agree well with those obtained from the more complicated Mie scattering theory. The differential attenuation and phase shift between horizontally and vertically polarized waves are also obtained using the proposed model and their calculated values compare favorably with available published results by Oguchi (oblate spheroid rain droplets) and Pruppacher and Pitter (deformed rain droplets).

ISSN:0895-2477    

DOI:10.1002/mop.4650080311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY