By Josh Perry, Editor
Researchers at Osaka University (Japan) developed a new computational algorithm that uses electromagnetic (EM) studies and circuit theory to calculate electromagnetic noise in electronic circuits, according to a report from the school.
A pulse signal induces a series of pulses on the transmission line (left). Improvement of the transmission line arrangement and lumped circuit connection provides “noise-free” signal transmission (right). (Osaka University)
EM noise, or interference, is caused by transmission lines and connectors and filters and passive devices have been added to circuits in an effort to reduce it. The new algorithm can be used in computer simulations of circuits with transmission lines and connects the partial differential equations used to solve transmission line problems with the ordinary differential equations used for lumped constant circuits.
“Previously, this solution required a method to replace lumped constant circuits with transmission lines, but this new method does not require such a replacement, allowing for more practical calculations” the article explained. “Their calculation method is for one-dimensional multi-conductor transmission lines, but they have already developed a calculation algorithm in two- and three-dimensional multi-conductor transmission lines (patent pending) as well, making it possible to advance its applied research.”
The algorithm can also be used to calculate the effects of EM noise as well as the heat created by noise, metamaterials, and antenna analysis.
The research was recently published in Scientific Reports. The abstract read:
“In order to find the origins of electromagnetic noise in the time domain, we formulate a system of lumped parameter circuits and multiconductor transmission lines (MTL).
“We present a discretized approach to treat any lumped parameter circuits and MTL systems, and the boundary conditions between these systems, where the lumped parameter circuits are described by coupled differential equations, and the MTL systems by coupled partial-differential equations.
“The introduction of the time-domain impedance and the element matrices enables us to perform a time-domain analysis that includes dependent sources and the coupling devices in the framework of the circuit theory. For three-line systems, we are able to calculate the coupling of the normal, common, and antenna modes, and to find out methods to reduce the noise.”