Fresh PCB Concepts: Assembly Challenges with Micro Components and Standard Solder Mask Practices
Elementary Mr. Watson: Retro Routers vs. Modern Boards—The Silent Struggle on Your Screen
Beyond Design: The Metamorphosis of the PCB Router
Does Copper Pour on a Signal Layer Decrease Signal-To-Signal Isolation?
April 7, 2022 | Steve Hageman, Analog HomeEstimated reading time: 1 minute
Does putting a ground pour on PCB signal layers make the isolation better or worse? It can go either way, but with the proper knowledge and application, this technique will improve your designs.
In this article, I’ll discuss how to simulate trace-to-trace isolation with true electromagnetic simulation software. We’ll also cover a variety of rules of thumb that can help you stay away from trouble.
Fact or Fiction?
Recently an acquaintance told me, “I have heard that putting a copper pour on a signal layer between traces actually makes the isolation between the traces worse.” I grabbed one of my RF boards and said, “If that is so, then how do all these RF boards that I have done with co-planar waveguide over ground manage to function? They all have copper pours on the signal layer, and they work to very high frequencies.”
Since co-planar waveguide over ground (CPWG), which is essentially “pouring copper on a signal layer,” is used for a lot of RF work, and is proven to work for very high-performance RF circuits, how did this contradictory opinion catch on in the industry?
To investigate this, I used a one-inch section of 50-ohm microstrip consisting of an aggressor trace from ports 1 to 2 and a victim trace running in parallel from ports 3 to 4. I used typical values for the dimensions as might be on a real PCB. The trace width is 20 mils, with a spacing of 60 mils from center to center, over an FR-4 substrate, 9.5 mils thick, with a modeled Er of 4.4.
To read this entire article, which appeared in the March 2022 issue of Design007 Magazine, click here.
Share on:
Suggested Items
The Evolution of Picosecond Laser Drilling
06/19/2025 | Marcy LaRont, PCB007 MagazineIs it hard to imagine a single laser pulse reduced not only from nanoseconds to picoseconds in its pulse duration, but even to femtoseconds? Well, buckle up because it seems we are there. In this interview, Dr. Stefan Rung, technical director of laser machines at Schmoll Maschinen GmbH, traces the technology trajectory of the laser drill from the CO2 laser to cutting-edge picosecond and hybrid laser drilling systems, highlighting the benefits and limitations of each method, and demonstrating how laser innovations are shaping the future of PCB fabrication.
Day 2: More Cutting-edge Insights at the EIPC Summer Conference
06/18/2025 | Pete Starkey, I-Connect007The European Institute for the PCB Community (EIPC) summer conference took place this year in Edinburgh, Scotland, June 3-4. This is the third of three articles on the conference. The other two cover Day 1’s sessions and the opening keynote speech. Below is a recap of the second day’s sessions.
Day 1: Cutting Edge Insights at the EIPC Summer Conference
06/17/2025 | Pete Starkey, I-Connect007The European Institute for the PCB Community (EIPC) Summer Conference took place this year in Edinburgh, Scotland, June 3-4. This is the second of three articles on the conference. The other two cover the keynote speeches and Day 2 of the technical conference. Below is a recap of the first day’s sessions.
Preventing Surface Prep Defects and Ensuring Reliability
06/10/2025 | Marcy LaRont, PCB007 MagazineIn printed circuit board (PCB) fabrication, surface preparation is a critical process that ensures strong adhesion, reliable plating, and long-term product performance. Without proper surface treatment, manufacturers may encounter defects such as delamination, poor solder mask adhesion, and plating failures. This article examines key surface preparation techniques, common defects resulting from improper processes, and real-world case studies that illustrate best practices.
RF PCB Design Tips and Tricks
05/08/2025 | Cherie Litson, EPTAC MIT CID/CID+There are many great books, videos, and information online about designing PCBs for RF circuits. A few of my favorite RF sources are Hans Rosenberg, Stephen Chavez, and Rick Hartley, but there are many more. These PCB design engineers have a very good perspective on what it takes to take an RF design from schematic concept to PCB layout.