The Knowledge Base: The Era of Advanced Packaging
Standard of Excellence: Finding and Developing Future Leaders in Manufacturing
Global Sourcing Spotlight: Navigating the Variables of Holiday Schedules in Global Sourcing
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
Global PCB Connections: Following DFM Rules Leads to Better Boards
12/18/2024 | Jerome Larez -- Column: Global PCB ConnectionsAs a PCB field applications engineer, ensuring smooth communication between PCB designers and fabricators is one of my frequent challenges. A critical part of that dialogue is design for manufacturing (DFM). Many designers, even experienced ones, often misunderstand or overlook important DFM considerations. They may confuse design rules with manufacturing minimums, leading to technically feasible designs that are difficult or costly to produce. In this column, I will clarify some common DFM guidelines and help designers understand the difference between “design rules” and “minimums” while sharing best practices that will simplify the production process and ensure the highest quality PCB.
Sayonara to the Last Standing Copper Foil Plant in North America
12/17/2024 | Marcy LaRont, I-Connect007In July 2021, PCB007 Magazine published an interview with Michael Coll and Chris Stevens of Nippon Denkai about the new acquisition by Nippon Denkai of the last-standing ED foil manufacturer in North America. The plant in Augusta, Georgia, was formerly owned by Oak Mitsui, Inc. and had been purchased by Nippon Denkai the previous March, after which significant investment was made with the expectation of providing more jobs.
SCHMID Group Unveils Enhanced InfinityLine H+ for Electroless Copper Deposition
12/16/2024 | SCHMID GroupThe SCHMID Group, a global leader in high-tech solutions for the electronics industry, proudly announces significant updates to its flagship InfinityLine H+ Electroless Cu system. Specifically designed for the production of high- performance advanced packaging applications using mSAP and SAP processes, the system reflects SCHMID’s expertise in horizontal electroless copper deposition.
OKI Develops PCB Technology with Stepped Copper Coin Insertion to Achieve 55 Times Better Heat Dissipation in Outer Space
12/12/2024 | BUSINESS WIREThe OKI Group printed circuit board (PCB) business company OKI Circuit Technology has successfully developed multilayer PCB technology with stepped copper coin insertion to achieve 55 times better heat dissipation compared to conventional PCB. The stepped copper coin is offered in two types, circular and rectangular, to suit the shape of the electronic component mounted on the PCB. OTC is working to develop mass-production technologies with the aim of introducing PCBs incorporating this new technology into markets for compact devices or devices used in outer space or other environments where air cooling technology cannot be used.
Fresh PCB Concepts: PCB Plating Process Overview
12/12/2024 | Team NCAB -- Column: Fresh PCB ConceptsIn this installment of Fresh PCB Concepts, Mike Marshall takes the helm stating: PCBs have been the platform for the interconnection of electronic components for decades. Because of process costs and other constraints, such as mechanical properties or size limitations of the alternatives, PCBs will remain the standard low-cost interconnection technology. Rapidly increasing performance and functionality requirements of wireless and high-speed devices have challenged the development and implementation of new manufacturing solutions.