Monthly Archives: October 2014

New article about inductive noise problems

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3D FEA Software Solves Tough Inductive Noise Problems
by Peter Markowski, Envelope Power, Ansonia, Conn.
A previous article on 3D electromagnetic finite element analysis (FEA) software explained how a new generation
of these tools, which includes EMS from EMworks, can be used for optimization of high-frequency transformer
design (see the reference.) In this article, I would like to show how the same software can help to solve difficult
layout problems in electronics, especially power electronics.
Switched-mode power supplies are notorious for hard-to-eliminate noise problems simply because we cannot
completely avoid proximity of high-power switching circuits and sensitive controls. Good engineering practices
such as minimizing high-frequency current loops and voltage surfaces, perpendicular arrangement of potential
source-target sets and using large copper planes for shielding are naturally a must. But without any way of
quantifying problematic phenomena it is impossible to know if we are pushing our luck and if we did the best we
could within the given constraints. In the end, we have to make a choice between unnecessarily conservative
designs and risking costly, time consuming (and stressful!) fixing of prototypes.

To read more, http://www.emworks.com/ckfinder/userfiles/files/design_EnvelopePower.pdf

HFWorks/S-parameters Analysis?

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Scattering parameters or S-parameters (the elements of a scattering matrix or S-matrix) describe the electrical behaviours of linear electrical networks when undergoing various steady state stimuli by electrical signals. Although applicable at any frequency, S-parameters are mostly used for networks operating at radio frequency and microwave frequencies where signal power and energy considerations are more easily quantified than currents and voltages. S-parameters change with the frequency are readily represented in matrix form and obey the rules of matrix algebra.The HFWorks/S-parameters analysis belongs to the high frequency electromagnetic, or the full wave, regime, i.e. Maxwell’s displacement current that couples the electric and magnetic fields is significant and thus taken into consideration. The vector wave equation, i.e. combination of the full Maxwell’s equations, is solved using vector finite element to obtain the S-parameters and the electric/magnetic fields and related design parameters. It has many practical applications, including:

• Connectors
• Filters
• Couplers
• Attenuators
• Terminators
• Baluns
• Integrated Circuit
• Waveguides
• Power dividers
• Multiplexers
• Power combiners
• Transitions