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The Shaughnessy Report: Always With the Negative Waves

When I started covering PCB design in the ‘90s, RF designers comprised a small percentage of the design community. Other than cellphones and handheld GPS devices, RF wasn’t seen very often outside of military, aerospace, and law enforcement applications. 

Now, RF is everywhere. Almost every electronic device in your house and pocket—your cellphone, tablet, laptop, smartwatch, and wireless/smart speaker—contains RF technology. The entire wearable segment is built on RF technology.

The RF arena has its own set of unique challenges. EMI and crosstalk can have a “field” day with RF signals. Parasitic inductance and capacitance are huge challenges in the RF space, and modeling is required to mitigate unwanted resonances. Precise impedance matching is necessary to avoid signal reflection; mismatches can cause signal degradation and reduce the efficiency of the end product. 

A variety of RF material flavors are available now, but some, such as PTFE-based laminates, are difficult to work with. Even the most minor variations in the fab process can have far-reaching effects on the RF signal. 

RF design is often called “black magic,” but designing an RF PCB isn’t that much different than designing a traditional circuit board—if you know what you’re doing. 

In the April 2025 issue of Design007 Magazine, our experts discuss the constantly evolving world of RF design, including the many tradeoffs, material considerations, and design tips and techniques that designers and design engineers need to know to succeed in this high-frequency realm.

We start with an interview with Alun Morgan, who discusses RF materials and the impact that laminate choice can have on your design. Columnist Vern Solberg shares his thoughts on proper stackup design techniques for RF PCBs; the wrong stackup can wreak havoc on an RF board. Zach Peterson discusses the most common challenges—and solutions—in RF design. Kirsten Zima delves into the issues of designing PCBs that feature multiple wireless technologies, such as GPS, Wi-Fi, and Bluetooth. 

Cherie Litson provides an overview of RF design engineering, including handy DFM tips. David Vye discusses RF design from an EDA tool company’s viewpoint, and Brent Mayfield does a deep dive into the development of RF materials. We also have an article on the use of UDHI in agricultural settings by Anaya Vardya, a column by Matt Stevenson, and reviews of IPC APEX EXPO and the Design Town Hall. 

Trade show season is underway. I hope to see you at PCB East. See you next month!

This column originally appeared in the April 2025 issue of Design007 Magazine.