Full-wave Equivalent Circuit Research Articles

Analysis of Elliptical Waveguides With Anisotropic Dielectric Layers

Our main objective is to extend the discrete mode matching (DMM) method to analyze multilayered elliptical fibers or transmission lines with elliptical dielectric layers. We generate the formulation for the full-wave equivalent circuit (FWEC) and derive the hybrid matrix elements for the dielectric layers in an elliptical coordinate system and then obtain the system equation of the structure. To demonstrate the technique, we analyze elliptical waveguides and compare the results with the data obtained by other authors and by commercial software.

Efficient Analysis of Inhomogeneous Dielectric Waveguides With Dielectric Strips and Microstrips Using Discrete Mode Matching Method

In this article, the discrete mode matching (DMM) method is extended to characterize multilayered transmission line structures with inhomogeneous anisotropic dielectric layers using only 1-D discretization. We have thoroughly discussed the procedure to analyze hybrid dielectric waveguides with dielectric strips and/or microstrips, i.e., metallization at the interfaces. The analysis of the structures is based on the full-wave equivalent circuit approach, which gives the generalized relation of the field components of the multilayered structure and the corresponding system equation. Accurate results are obtained with very less computational effort. The dispersion curves and the electric field intensity distributions are presented for various dielectric waveguides and validated with the commercial software.

Multilayered Transmission Lines on Quasi-planar Substrates With Anisotropic Medium

Abstract. This paper exhibits the extension of the discrete mode matching (DMM) method to analyze conformal structures with anisotropy. It represents a simple formalism as a basis to analyze multilayered structures with quasi-planar anisotropic dielectric layers. The dyadic Green's function is then calculated using a full-wave equivalent circuit (FWEC) of the structure, where each layer is represented with the hybrid block consisting of the tangential field components. The application is demonstrated by computing propagation constants for partially filled quasi-planar waveguides and microstrip lines with isotropic, uniaxial and biaxial anisotropic dielectrics.

Lightning Propagation Analysis on Telecommunication Towers Above the Perfect Ground Using Full-Wave Time Domain PEEC Method

Lightning surge propagation on telecommunication towers is essential to lightning protection design. Analysis of very fast surges in a telecommunication tower requires a full-wave solution of Maxwell's equations. This paper proposes a full-wave time domain partial element equivalent circuit (PEEC) method considering the effect of ground to evaluate the surge currents and voltages on vertical structures. The PEEC of the formulation is provided by using the method of image. This method can take into account the attenuation of the lighting surges, and has the potential to be implemented as a new type of solution for general lightning surge analysis. The proposed method is validated numerically with the finite-difference time domain method, and is used to analyze the surge propagation on cables mounted on two typical grounded telecommunication towers. The simulation shows that both the location of cable installations and the type of towers have a significant influence on the lightning protection performance.

Analysis of Circular and Noncircular Waveguides and Striplines With Multilayered Uniaxial Anisotropic Medium

A simple procedure to analyze multilayered transmission lines with circular or quasi-circular uniaxial anisotropic dielectric layers is presented. It is based on an extension of the discrete mode matching method to analyze conformal structures with anisotropy. A generalized relation of the field components, which can be represented by a full-wave hybrid matrix for each layer, is used and then the dyadic Green's function is obtained using a full-wave equivalent circuit of the structure. The application is demonstrated by computing dispersion characteristics for graded-index optical fibers, elliptical waveguides, and elliptical stripline structures with uniaxial anisotropic dielectric.

Full‐wave equivalent circuit for the analysis of multilayered microwave structures with anisotropic layers

A simple formalism is presented as a basis to analyse planar microwave structures with uniaxial anisotropic materials having either electric or magnetic anisotropy or both. It involves a generalised relation of the field components of the multilayered structure, which can be represented by a full-wave hybrid matrix for each layer. Thus, for stratified structures, the system equation can be obtained by using a full-wave equivalent circuit. The application is demonstrated by analysing the well-known example of a two-layer waveguide filled with different uniaxial anisotropic dielectric material.

Analysis of Conformal Microstrip Antennas With the Discrete Mode Matching Method

An extension of the discrete mode matching (DMM) method is used to analyze microstrip antennas conformed to cylinders. The structure needs to be discretized only along the azimuthal and the axial directions by sampling the fields and current densities in the interfaces between dielectric layers. The solution in the radial direction is obtained analytically with the dyadic Green's function, which is calculated using the full-wave equivalent circuit (FWEC) in the spectral domain. The structure is truncated in the axial direction by employing absorbing boundary conditions (ABCs). The mathematical formulation is given in this paper, followed by its application to compute the main properties of conformal microstrip antennas, such as resonant frequency, radiation patterns and input impedance. Validation with the commercial software HFSS has been done and good agreement between the results has been observed.

Fast analysis of cylindrical microstrip lines printed on substrates composed of multiple layers

This letter presents an analysis of microstrip lines that are printed on substrates composed of numerous dielectric layers using a fast technique that comprises the full-wave equivalent circuit and the discrete mode matching method. The validation of the proposed formulation has been done with a commercial package based on the finite-element method and very good agreement has been obtained. As a special application of our technique, we consider the analysis of microstrip lines printed on substrates with dielectric constants that vary according to given graded-index profiles. The profiles are modelled by replacing the substrate by numerous homogeneous dielectric layers. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1626–1628, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25276

Compact Broadside Coupled Directional Coupler Based on Coplanar CRLH Waveguides

A compact broadside coupled (BSC) backward directional coupler based on composite right/left-handed (CRLH) coplanar waveguide (CPW) is proposed. The design is symmetric on both sides of the substrate and comprises of series gap capacitor, broadside-coupled capacitor, and shunt meandering short-circuited stub inductor. Compared to existing directional couplers, the proposed coupler has much smaller size, broader bandwidth, phase balance and easy fabrication. An equivalent circuit model including series inductance, capacitance, shunt inductance and capacitance tank has also been established. Good agreement between the full-wave simulation and equivalent circuit model verifies the effectiveness of the proposed circuit model. Measured bandwidth from 9.9 ∼ 14.7 GHz centered at 12 GHz (40%) is observed with the device size of 1.8 × 1.3 cm2.

Flip-Chip Interconnect for Coplanar Strip Lines

A flip-chip interconnect configuration with coplanar strip (CPS) lines on printed circuit boards (PCBs) is reported for millimeter-wave applications. For CPS lines, the signal and ground electrodes both lie on the top surface of a chip or substrate. The flip-chip configuration was designed and implemented using a test chip on a dielectric board. Geometrical parameter analysis was carried out using full-wave simulation and equivalent circuit model for wideband performance. The chip was connected to the board using solder bumps. For a typical flip-chip assembly, the measured insertion loss is less than 3dB for frequencies of up to 35GHz and the return loss is higher than 15dB for frequencies of up to 29GHz using CPS flip-chip configuration.

Analysis of Graded-Index Fibers Using a Full-Wave Equivalent Circuit

This paper presents an efficient approach for the analysis of graded-index profile waveguides. The variation of the index of refraction is modeled considering a sufficient number of concentric dielectric layers, each with a different index of refraction. The propagation constant in the layered structure is calculated by setting up a full-wave equivalent circuit, which allows the derivation of the system equation for the whole structure. Two examples are given, including validation with the commercial software Ansoft HFSS

Analysis of cylindrical microstrip lines using the discrete mode matching method

This letter presents an extension of the discrete mode matching (DMM) method to analyze microstrip lines conformed on cylinders. The DMM is well suited to the analysis of multilayered structures, since the fields must be only sampled at the interfaces between the dielectric layers. For the case of cylindrical microstrip lines, the structure is discretized only along one direction, whereas the analytical solution is obtained in the other with the Green's functions calculated using a full-wave equivalent circuit. The mathematical formulation of the present extension is given in this letter, followed by its application to compute the propagation constants for cylindrical microstrip lines

Full-wave equivalent circuit model for 2D conductor

A full-wave equivalent circuit model for any arbitrary 2D conductor has been developed. The SPICE-compatible full-wave circuit model could be easily integrated into any circuit-based simulator to study the influence of any conductor on high-speed circuit performance.

Analysis of microstrip lines in multilayer structures of arbitrarily varying thickness

A general approach to the full-wave analysis of microstrip lines in multilayer dielectrics of arbitrarily varying thickness is developed. It is based on the discrete mode matching technique (DMM) and uses a full-wave equivalent circuit for the stratified structure, which is simple to apply in a numerical procedure, As an example, the propagation constant of a microstrip line in the interface of two dielectrics as a function of different shape characteristics is computed.

Accuracy and stability improvements of integral equation models using the partial element equivalent circuit (PEEC) approach

The partial element equivalent circuit (PEEC) technique is a formulation which transforms an electric field integral equation (EFIE) into a full-wave equivalent circuit solution. In this paper, improvements are made to the PEEC model through the development of a refined method of computing both the partial inductances as well as the coefficients of potential. The method does not increase the number of unknowns. In addition, damping is added to the PEEC model in order to further reduce nonphysical resonances which may occur above the useful frequency range, The observations and solutions presented in this paper are especially important for time domain solvers. The effectiveness of the method is illustrated with several examples.

CAD-oriented fullwave equivalent circuit models for waveguide components and circuits

New multimode equivalent circuit models for single and cascaded E-plane and H-plane step discontinuities in rectangular waveguides are presented. The computer-aided design (CAD)-oriented equivalent circuit models enable rigorous and efficient fullwave analysis of waveguide components and circuits entirely by circuit simulation. The method has been implemented on the microwave circuit simulator Libra and applied to waveguide structures containing single and cascaded irises and stub discontinuities. Comparisons of circuit simulation results for single and cascaded inductive irises as well as a single and three E-plane stubs with the standard mode-matching method show perfect agreement. Results of a Ka-band bandpass filter analysis are in good agreement with a mode-matching solution that includes the correct edge condition.