# Electromagnetic Simulation and Applications

The application of the electromagnetic field theory in microwave circuits has become a must in the last years. The mutual effects of electromagnetic fields and waves within a circuit and their neighborhood increase with higher frequencies. A realistic modeling and physical description of circuits and modules is only possible by understanding the effects of electromagnetic fields.  The mathematical model describing the physical nature is based on Maxwell’s equations. They connect the electric and magnetic fields to a unique system explaining the electromagnetic functionality. As the equations are rather difficult to solve even for small problems, special numerical procedures are used to obtain results for practical tasks – no matter whether it is about simple line structures on chips, transitions between different circuit parts or mountings, or the influence of cases onto the electric behavior. Presently, it becomes more and more important to describe, understand, and define measurement probes (often a coaxial tube with 3 attached measurement needles). In order to find a standard which allows to be applied in the industry for congruent results in the measurement of high-frequency circuits, it is important to understand the electromagnetic field behavior of the probe system. This includes desired effects as well as unavoidable parasitic effects.

One of the most important numerical solvers uses the so-called “Finite Difference” approach which discretizes a spatial region into small subcells in which the fields are assigned to certain knots and are, in turn, connected with all neighboring cells to form a system of equations (matrix). This method of “Finite Differences” is used at the FBH for investigations and design purposes. Due to the increasing amount of data in most cases, the time domain solution is applied using the software Microwave Studio from CST. The spectrum of requirements covers a wide range from simple microstrip lines in low GHz regions up to complex geometries in the THz region. Beyond these internal investigations, the FBH offers its competence also to industrial partners for solving detailed problems.

## Applications covered - overview

• Modelling of passive elements in integrated circuits (GaN, InP,….)
• Packaging and multi-chip modules (flip-chip, thin-film, LTCC, cases)
• Sub-millimeterwave lines
• Analysis of parasitic effects und uncertainties in high frequency measurements and calibration approaches

Our institute is capable of  extensive experience on all of these fields due to manifold projects and request by industrial partners worldwide.