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The recently proposed theory of Maxwellian circuits is demonstrated for applications to linear wire scatterers as well as to linear antennas. It is shown that for each integral equation of thin wire type, there exist coupled linear ordinary differential equations of currents and voltages, the solutions of which are identical to the integral equation, if the same boundary conditions of the integral equation are applied. The subsequence is that the coupled differential equations can be interpreted as equivalent circuit of new type named Maxwellian circuit. The equivalent circuit can provide physical insights to design engineers and computational advantages for broadband calculations. The highlight of this paper is to show both theoretically and numerically that the Maxwellian circuit components depend only on the geometry of the problem, not on the excitation or boundary conditions at the terminals. Index Terms--Generalized transmission line equation, Maxwellian circuits, method of moments (MoM), wire antennas and scatterers.

The main idea of Maxwellian circuits is that any wire structure, such as a thin wire antenna or a microstrip structure, can be represented by equivalent distributed circuits, the solution of which is identical to the solution of Maxwell's equations of that structure. Such circuits are said to be Maxwellian [1]. In this paper, the Maxwellian circuits are implemented into a curved structure, i.e., spiral antennas. Since a spiral antenna has much stronger dispersion and mutual couplings than a straight antenna, the most challenging thing for the spiral antenna is how to realize the broadband equivalent circuits. Numerical results for the two-arm Archimedian spiral antenna show that the solutions of its Maxwellian circuits over a quite wide frequency band are the same as those obtained by the conventional integral equations, but solving the circuits represented by the differential equations is much more efficient than solving the integral equations. Index Terms--Maxwellian circuits, method of moments (MOM), spiral antennas.

Fun impedance matrices of the method of moments (MoM) type have been decomposed into sparse matrices in the application of on-surface measured equation of invariance (OSMEI) [1], [2]. The objectives in [1] and [2] are to find continuous current distributions on scatterers. Thus, the concept of metron and measure is justified under the postulate that the local relation between fields and current densities is an invariant of the excitation. In this paper, we have extended the concept to dipole arrays, where the objective is to find the discrete driving point currents. Numerical results show that using the windowed metrons presented in this paper, the sparsity rate of the sparse matrices can be kept within 1%, while the E- and H-plane patterns are still in good agreement with the MoM results except for the farthest side lobes of the H-plane patterns. Index Terms--Antenna, matrix decomposition, measured equation of invariance.

Circular loops are useful fundamental devices, subjects of many investigations. Before the era of the method of moments (MoM), it was difficult to analyze a circular loop because it was hard to find the current distribution on the loop. The classical investigations on circular loops involve fairly complicated mathematical analyses. In this paper, based on the theory of Maxwellian circuits (MC), it is discovered that the current of a circular loop is the solution of a classical wave equation with complex constant parameters. Once the parameters are determined, the current may be solved analytically or by simple numerical methods. Very broad band computations of circular loops up to 40 GHz have been performed. It shows that the Maxwellian circuits formulations can indeed simplify the analyses of conducting circular loops and provide valuable insights to RF engineers. [ABSTRACT FROM AUTHOR]

The main idea of Maxwellian circuits is that any wire structure, such as a thin wire antenna or a microstrip structure, can be represented by equivalent distributed circuits, the solution of which is identical to the solution of Maxwell's equations of that structure. Such circuits are said to be Maxwellian [1]. In this paper, the Maxwellian circuits are implemented into a curved structure, i.e., spiral antennas. Since a spiral antenna has much stronger dispersion and mutual couplings than a straight antenna, the most challenging thing for the spiral antenna is how to realize the broadband equivalent circuits. Numerical results for the two-arm Archimedian spiral antenna show that the solutions of its Maxwellian circuits over a quite wide frequency band are the same as those obtained by the conventional integral equations, but solving the circuits represented by the differential equations is much more efficient than solving the integral equations. [ABSTRACT FROM AUTHOR]

Full impedance matrices of the method of moments (MoM) type have been decomposed into sparse matrices in the application of on-surface measured equation of invariance (OSMEI) [1], [2]. The objectives in [1] and [2] are to find continuous current distributions on scatterers. Thus, the concept of metron and measure is justified under the postulate that the local, relation between fields and current densities is an invariant of the excitation. In this paper, we have extended the concept to dipole arrays, where the objective is to find the discrete driving point currents. Numerical results show that using that windowed metrons presented in this paper, the sparsity rate of the sparse matrices can be kept within 1%, while the E- and H-plane patterns are still in good agreement with the MoM results except for the farthest side lobes of the H-plane patterns. [ABSTRACT FROM AUTHOR]

In this paper, a new analysis for a double step microstrip discontinuity is presented by using generalized transmission line equations [1]. The new analysis is based on a new concept of a finite-length transmission line integrated with its double step discontinuity so that the double step discontinuity is regarded as a finite-length nonuniform transmission line and the generalized equations could be directly implemented. Since the generalized equation coefficients are determined by dynamic numerical methods and the coefficients are invariant with the line excitation and load, the equations are dynamic rather than TEM. The interested discoveries are that the generalized equations for the whole double step structure or a partial double step structure can give us the same results and the generalized equations have broadband frequency characteristics. For the double step structure used in this paper for the analysis, the S-parameters for a frequency band from 0.5 GHz to 10 GH.z can be well calculated by using only two separately generalized equations at frequency of 3 GHz and 8 GHz. [ABSTRACT FROM AUTHOR]

A new numerical model of microstrip transmission line circuits in terms of distributed circuit parameters is here illustrated. Based on full-wave electromagnetic results, the extraction methods of these distributed circuit parameters on different types of microstrip transmission line circuits are introduced. As a preparatory experiment, an improved CAD method using this model is tested on microstrip low-pass filter. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The online FDTD method derived from general transmission line equations [1] has been introduced in [2, 3]. Following the research on non-uniform transmission lines, we further explore the application of online FDTD in the microstrip cross and T-junction structures. As the theoretic difficulties of modeling the connection of multi-transmission lines have been solved, many microstrip structures that have cross or stub substructures can be easily simulated by online FDTD. Three examples are presented to test the validity of this application. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 184–187, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10715 [ABSTRACT FROM AUTHOR]

An improved conformal FDTD algorithm for microwave planar structure is presented in this paper. To achieve high-level accuracy and universality, but still keep the efficiency of the FDTD method, improved locally conformal algorithm and non-uniform orthogonal grids are employed to model the planar metal structures. All field components in destructed lattice are updated using locally conformal integral form of equations in order to achieve more accurate results. And with non-uniform orthogonal grids, arbitrary-shape metal strips can be modeled without generating a lot of unstructured meshes. In this algorithm, additional updating procedures for the fields in the destructed Yee lattice are no longer needed. The time marching procedures remain almost as simple as a uniform rectangular grids scheme. An oblique positioned microstrip stub structure is tested as an example to show the validity of this algorithm. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 219–224, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10562 [ABSTRACT FROM AUTHOR]

General transmission-line equations based on the theory of differential equations [1] were introduced in [2] and [3]. The equations' dispersion characteristic of a microstrip low-pass filter is studied. The parameters L, C, α, and β of general transmission-line equations are found to be almost invariant to frequency in the passband of the microstrip low-pass filter. By restoring current and voltage distributions with the use of equations in both frequency and time domains, the broadband property of these equations on the microstrip low-pass filter is evident. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 123–126, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10250 [ABSTRACT FROM AUTHOR]

Analyzes a reflector antenna using the finite-difference (FD) method. Calculation of the induced current densities on an axially symmetric parabolic reflector; Effect of the standing wave of current densities on side lobes; Discussion of the occurrence of singularities of FD equations; Results of induced current densities on the surfaces of reflector antennas.

Presents a study that calculated the electric field distribution in the slot cut in the outer conductor of the coaxial cable using the finite-difference time-domain method (FDTD). Discussion on radiation harmonics and resonant points of the leaky coaxial cables; Information on FDTD formulas and radiation field integration; Results of the field distribution in slots.

Presents a study which proposed the domain-decomposed measured equation of invariance (DDMEI) method for field computation in single and multiple regions. Measured equation of invariance matrices in the DDMEI method; Application for the scattering of single conducting cylinders; Application for the radiation of wire arrays; Application for capacitance computation of multiconductor transmission lines.

Focuses on the measure equation of invariance (MEI), a developed computational method which allows finite difference (FD) or finite-element (FE) mesh to be terminated very closely. Results shown by the use of microstrip antennas; How the MEI method may be applied to microstrip structures; Details as to why well-verse readers may reproduce results with less effort.

The measured equation of invariance (MEI) is a newly developed computational method which allows finite-difference or finite-element meshes to be terminated very closely to objects of interest [1]. In this paper, it is demonstrated that the MEI method may be applied to layered structures where the Green's functions are known. In that case, the MEI method is applied almost as conveniently as it is in free space, except that the Green's function is changed to that of the layered structures. [ABSTRACT FROM AUTHOR]

Focuses on the scheme of novel fast iteration technique for two-dimensional scattering of conducting cylinders. Calculation of the matrix decomposition in the system; Application of measured equation of invariance and method of moments; Wavelengths of the computation speed in electromagnetic scattering.

Deals with a study focused on the application of discrete periodic wavelets (FDPW) as metron currents to measured equation of invariance (MEI) method. Description of the FDPW; Numerical results of the study; Conclusion.