Eric Bogatin, Signal Integrity Journal Technical Editor
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Eric Bogatin is Technical Editor at Signal Integrity Journal and the Dean of the Teledyne LeCroy Signal Integrity Academy. Additionally, he is an Adjunct Professor at the University of Colorado - Boulder in the ECEE Dept. Eric improves the signal to noise ratio by sorting through all of the information available and finding the best quality content to publish on signalintegrityjournal.com.

Signal Integrity

I kissed a Lot of Frogs in June 2021: Here are two Princes

June 22, 2021

There are hundreds of webinars released each month. Many of them are frogs: you waste an hour of your time and walk away with nothing except a bad taste, like kissing a frog. I sacrificed hours of my time and precious brain cells watching too many webinars that turned out to be frogs. But, here are two webinars that turned into princes. 

The first webinar was about Additively Manufactured Electronic Circuits by our sister publication, Microwave Journal, with Pat Hindle and Jaim Nulman, the CTO and executive VP of Nano Dimensions. In the last ten years, we have been in the early stages of a revolution in 3D printing of mechanical parts using plastics and metals. 

I think there is the potential for just as large if not a greater opportunity for 3D printed electronic circuits. This webinar introduces a new option that prints both highly conductive materials and dielectric materials on the same layers with high resolution and can be repeated for more than 50 layers.

Whenever we look at a new technology, we always want to think about what the killer apps are. What are the types of products or designs this new technology can enable that cannot be done any other way? Nano Dimensions suggest that four important applications are: reduced size and weight for space applications, meta material structures that are inherently complex 3D combinations of dielectric and conductor, integrated electronics and mechanical structures or 3D antennas, such as shown in Figure 1 and for captive, rapid prototyping of complex circuit boards where keeping all design information in house is critical. 

Figure 1. An example of a 3D printed structure with wiring and mechanical features, from Nano Dimensions.

This is just one example of a potentially enabling technology for the wide scale introduction of 3D printed electronics. Don’t think about this technology as replacing conventional circuit boards, but as enabling whole new products or applications. 

My second choice for June is a presentation on Fast Circuits for Fast Cars, by Dr. Min Zhang, Founder and Principle EMC Consultant with Mach One Design Ltd out of Oxford, England. This is part of the EMC LIVE Automotive series of presentations. The name of the game in electric vehicles is improved efficiencies. This is the driving force (pun intended) for higher voltage so there are lower IR losses, and for faster switching MOSFETS so that there is less IR losses when the gates pass through their linear region. 

The combination of higher voltages and shorter rise times mean more EMI and noise problems. For example, Figure 2 shows the current waveform to a motor with broadband and high frequency noise. The sharp, high frequency glitches are what can contribute to EMI.

Figure 2. An example of the current to a motor showing the switching noise that can result.

As with many EMC issues, Dr. Zhang says that 90% of the problems arise from “ground” issues. You may think you have a good DC connection between multiple ground points, but there is no such thing as an ideal short. There is always some loop inductance which can be a source of voltage to drive radiating currents between ground structures.