Andreas Mantzke

Efficient Broadband Circuit-Modeling Approach for Parallel-Plane Structures of Arbitrary Shape

A methodology for creating highly efficient and inherently stable equivalent-circuit models for arbitrarily shaped parallel-plane pairs is presented. Based on Greens function with accelerated convergence, a general impedance expression is derived for circular ports, comprising the static capacitance and inductances and a small number of resonant terms. It can be directly cast into an equivalent multiport circuit for arbitrary number of ports, enabling the application in a SPICE circuit-simulation environment for broadband system analysis with active, passive, and nonlinear components. The equivalent-circuit elements are determined by a simple finite-difference scheme in combination with an analytical port model, which allows us to perform the required modal and the quasi-static analysis with a uniform mesh. Validation by numerical full-wave field simulations demonstrates the versatility of the suggested approach and the high computational savings of several orders of magnitude in frequency and time domain.

A Foster-Type Field-to-Transmission Line Coupling Model for Broadband Simulation

A passive and inherently stable multiport equivalent circuit for lossy transmission lines is presented. The convergence of the infinite modal representation is accelerated by appropriate inductances, for which an exact closed-form expression is developed. The order number of the truncated modal circuit is estimated by a simple relation, according to the required signal bandwidth. The coupling of arbitrary external electromagnetic fields is incorporated by a limited number of corresponding modal sources. The accuracy and versatility of the suggested SPICE-compatible equivalent circuit is demonstrated by examples in frequency and time-domain, including nonlinear terminations.

Broad-Band Modeling of Passive Power-Supply Filter Structures

This paper shows an approach for the broad-band modeling of passive power-supply filter structures, which may be applied to the virtual filter design. The most important advantage of this technique is the possibility of considering the parasitic and functional behavior of a power-supply filter in the same simulation. The approach provides a 3-D model of the filter structure based on a differential field solver. Moreover, the passive components are approximated by combined behavioral-physical 3-D models, which allow the simulation of this structure and the physical volumetric modeling of the current distribution in the components. Thus, the functional behavior of the filter is modeled taking into account all the high-frequency effects (equivalent serial inductance, equivalent serial resistance, parasitic capacitances, punch-grid issues, couplings between components, couplings between interconnections, losses in the plastic environment, etc.). This paper provides a validation of the approach by measurements of a simplified hardware sample and of an industrial filter sample as well.

Network modeling of vertical signal interconnections in parallel reference plane structures on printed circuit boards

Signal path transitions through parallel reference plane structures on printed-circuit boards are investigated. The analysis is based on an equivalent circuit including the interconnect inductances, the signal source and load impedance. All required network elements can be calculated by simple formulas, including simple closed-form expressions for the self and mutual inductances in the central board region. Validation of the predicted network model by measurement shows a good agreement with respect to engineering purposes.

Efficient Modal Network Model for Nonuniform Transmission Lines Including Field Coupling

A passive and inherently stable Foster-type multiport equivalent-circuit representation for nonuniform, lossy transmission lines is presented within the validity range of quasi-TEM mode propagation. The approach is based on the eigenfunction expansion. Convergence of the infinite modal representation is accelerated by quasistatic inductances. The required modal and quasistatic analyses are implemented numerically with the method of finite differences (FD) utilizing the same FD operator. The model order of the equivalent circuit is estimated by a linear relation with respect to the required bandwidth. Without increasing significantly the complexity of the model, the influence of an external electromagnetic field is considered by equivalent field sources, which are also calculated by an FD algorithm. The efficiency and applicability of the suggested SPICE compatible model is compared with the ladder network and is demonstrated by examples in frequency and time domain, including nonlinear terminations.

Efficient analysis and reduction of magnetic near-field-coupling in mixed-signal PCBs via the reciprocity principle

The problem of analysis and reduction of the magnetic near-field coupling on the PCB-level is investigated by exploiting the reciprocity principle. The magnetic near-field coupling is described by the mutual inductance between victim and aggressor circuit. Based on the reciprocal magnetic field of the victim circuit, two methods are introduced, which can reduce this mutual inductance by magnetic flux compensation through a novel guard trace design or optimal placement of critical components. The proposed reduction methods are demonstrated by an example of a real hearing aids PCB and validated by 3D fullwave-simulation.

Broadband equivalent-circuit model for non-uniform transmission lines

A passive and inherently stable Foster equivalent-circuit multiport representation for non-uniform, lossy transmission lines is presented. The method is based on an eigenfunction expansion, where the eigenfunctions are determined numerically with the finite difference method (FD). An efficient model order reduction is achieved by appropriate inductances that are extracted with the same FD operator. The order number of the truncated modal circuit is simply estimated, according to the required signal bandwidth. The accuracy and versatility of the suggested SPICE-compatible equivalent-circuit is demonstrated by examples in frequency and time-domain, including nonlinear terminations.

Efficient FEM-Based Modal Circuit Representation of Arbitrarily Shaped Plate Pairs

A novel finite element method-based technique for the calculation of all circuit parameters of an efficient broadband equivalent network representation of parallel-plane pairs with arbitrary geometry is presented. It is based on an eigenvalue analysis in combination with the solution of the quasi-static Poisson equation for the magnetic vector potential. Compared with a recently presented simple finite difference scheme, the suggested FEM approach considerably reduces the modeling and computational effort, enabling an adaptive meshing in the presence of small circular ports. The proposed approach is validated by a practical example, demonstrating the considerable computational savings and the versatility for practical applications.

Broadband Equivalent-Circuit Model for Uniform Multiconductor Transmission Lines

A passive and inherently stable Foster equivalent-circuit representation for uniform multiconductor transmission lines for moderate losses is presented. The method is based on an analytic eigenfunction expansion. An efficient model-order reduction is achieved by appropriate inductances that are extracted by a quasistatic approach. The order number of the truncated modal circuit is simply estimated, according to the required signal bandwidth. The accuracy and versatility of the suggested SPICE-compatible equivalent circuit is demonstrated by examples in frequency and time domain, including nonlinear terminations.

Modal equivalent-circuit representation of inhomogeneous transmission lines with arbitrary terminations for efficient broadband simulation

A passive and inherently stable Foster equivalent-circuit multiport representation for non-uniform, lossy transmission lines is presented. The method is based on an eigenfunction expansion, where the eigenfunctions are determined numerically by the finite difference method (FD). An efficient model order reduction is achieved by appropriate inductances that are extracted with the same FD operator. The order number of the truncated modal circuit is simply estimated, according to the required signal bandwidth. The accuracy and versatility of the suggested SPICE-compatible equivalent-circuit is demonstrated by an example in the time-domain, including non-linear terminations.