Jeannick Sercu

Mixed potential integral equation technique for hybrid microstrip-slotline multilayered circuits using a mixed rectangular-triangular mesh

In this paper, a mixed potential integral equation (MPIE) formulation for hybrid microstrip-slotline multilayered circuits is presented. This integral equation is solved with the method of moments (MoM) in combination with Galerkins method. The vector-valued rooftop functions defined over a mixed rectangular-triangular mesh are used to model the electric and magnetic currents on the microstrip and slotline structures. An efficient calculation technique for the quadruple interaction integrals between two cells in the system matrix equation is presented. Two examples of hybrid microstrip-slotline circuits are discussed. The first example compares the simulation results for a microstrip-slotline transition with measured data. The second example illustrates the use of the simulation technique in the design process of a broadband slot-coupled microstrip line transition. >

Full-wave space-domain analysis of open microstrip discontinuities including the singular current-edge behavior

A full-wave space-domain analysis is presented for the high-frequency characterization of microstrip discontinuities. This approach solves the electric field integral equation (EFIE) for the surface current density on the microstrip using the method of moments. The current expansion functions incorporate the singular edge behavior of the surface current, yielding a very accurate current modeling. Special attention is devoted to the analytical treatment of the singular terms in the electric field Greens dyadic. The numerical results focus on the S-parameters of some simple microstrip discontinuities and the comparison with results obtained with other techniques and from measurements. >

Surface Current Modelling of the Skin Effect for On-Chip Interconnections

In this paper, the skin effect for 2-D on-chip interconnections is predicted using a recently developed differential surface admittance concept. First, the features of the new approach are briefly recapitulated and details are given for a conductor with rectangular cross-section. Next, the 1-D situation is studied as a limiting case of the 2-D situation. The relationship with a local impedance formulation is investigated and illustrated with a numerical example. Finally, the new method is used to determine inductance and resistance matrices of 2-D on-chip interconnect examples with specifications taken from the international technology roadmap for semiconductors. Extra capacitance data are also provided.

Recent trends in the integration of circuit optimization and full-wave electromagnetic analysis

In this paper, we provide an overview of some recent trends for the general electromagnetic (EM) circuit co-optimization approach based on an electromagnetic database (EMDB). This study is the result of long-standing efforts toward the development of an efficient planar EM simulator and its seamless integration in and combination with a circuit design environment. Two complementary techniques are put forward to build an EMDB model. Flexibility, accuracy, and computational efficiency of both techniques are validated by several examples.

Characterisation of TEM and non-TEM planar transmission lines with a full-wave 3D field analysis technique

A full-wave 3D method of moment analysis technique is used to simulate a finite length planar transmission line embedded in a multilayered medium. The circuit parameters of the transmission line follow from the identification of the field simulation results with a two-port equivalent circuit. A new de-embedding technique is used to remove the influence of the port discontinuities. The circuit model of the transmission line provides a new 3D calculation technique of the characteristic impedance of both TEM and non-TEM planar transmission lines.

Electromagnetic/Circuit co-optimization of lumped component and physical layout parameters using generalized layout components

This paper describes the concept of a generalized parametric layout component which enables one to simultaneously optimize the physical layout variations together with lumped passive and active component parameters. This is realized by a seamless integration of a electromagnetic simulator within a circuit simulation and optimization tool. The electromagnetic S-parameter model is generated dynamically for each set of layout component parameters, as selected by the optimizer. An electromagnetic model database keeps track of the generated S-parameter models for later reuse. This concept is illustrated in the design of an RF board low noise amplifier circuit.

Rigorous Analysis of Internal Resonances in 3-D Hybrid FE-BIE Formulations by Means of the Poincaré–Steklov Operator

3-D hybrid finite-element (FE) boundary integral equation (BIE) formulations are widely used because of their ability to simulate large inhomogeneous structures in both open and bounded simulation domains by applying each method where it is the most efficient. However, some formulations suffer from breakdown frequencies at which the solution is not uniquely defined and errors are introduced due to internal resonances. In this paper, we investigate the occurrence of spurious solutions resulting from these resonances by using the concept of the Poincaré-Steklov or Dirichlet-to-Neumann operator, which provides a relation between the tangential electric field and the electric current on the boundary of a domain. By identifying this operator in both the FE and BIE method, several new properties of internal resonances in 3-D hybrid FE-BIE formulations are easily derived. Several conformal and nonconformal formulations are studied and the theory is then applied to a scattering problem.

Generalized polygonal basis functions for the electromagnetic simulation of complex geometrical planar structures

This paper describes the generalization of the well known rectangular and triangular rooftop functions to polygonal subdomains. The rooftop functions are commonly used for the discretization of planar currents in electromagnetic simulators. The new generalized polygonal functions allow for a more efficient meshing of complex geometrical structures in terms of polygonal shaped cells. They naturally model the current flow in the polygonal cells, satisfy the current continuity relation and their usage significantly enhances the electromagnetic simulation performance for complex geometrical structures. The increased simulation performance is demonstrated for a complex RF board interconnection layout.

Generalized Poisson-Neumann polygonal basis functions for the electromagnetic simulation of complex planar structures

Rooftop functions are commonly used for the discretization of planar currents in electromagnetic (EM) simulators. We describe the generalization of the rectangular and triangular rooftop functions to arbitrary polygonally shaped subdomains. It is shown that these generalized basis functions are solutions to a pertinent Neumann-Poisson problem, and we derive the integral equations satisfied by these basis functions. The new generalized polygonal functions allow for a more efficient meshing of complex geometrical structures in terms of polygonally shaped cells. They naturally model the current flow in the polygonal cells, satisfy the current continuity relation, and significantly enhance the EM simulation performance for complex geometrical structures. The increased simulation performance is demonstrated for a complex radio-frequency board interconnection layout and a spiral inductor on a silicon substrate.

A New Mesh Reduction Technology for the Method of Moments Modelling of Planar RF and Microwave Interconnects

This paper describes a new mesh reduction technology that significantly increases the electromagnetic modelling efficiency of planar RF and Microwave interconnect structures. This technology reduces the redundancy in the method of moments equations due to the geometrical complexity of the structure. It comprises a generalization of the basis functions used in the discretization of the surface currents. The generalized basis functions allow for a more efficient meshing of complex geometrical structures in terms of polygonal shaped cells. The increased simulation performance is demonstrated for a complex microwave package interconnection structure.