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MAY 2026 I I-CONNECT007 MAGAZINE 105 ness, material properties, and copper geometry all contribute to defining the impedance. If you treat the stackup as an afterthought, you're essentially designing a road without knowing its width, sur- face, or even its makeup. But when you define it intentionally, you're setting the rules of the envi- ronment before a single trace is routed. Most assume this is about perfection. It's not. The goal is predictability. You don't need every trace to be identical, but you do need every critical signal to see a consistent environment along its path. That means minimizing unnecessary width changes, avoiding breaks in the reference plane, controlling layer transitions, and being deliber- ate about how signals move from one part of the board to another. Below the Surface Looking Ahead to Where Integration Actually Happens Progress in RF rarely arrives and suddenly rewrites the rules. What actually moves perfor- mance forward almost always happens in the seams, the interfaces, the choices that determine whether individual parts are allowed to work to- gether, or forced to fight one another. So, when we look ahead in RF systems—from DC through millimeter-wave—the most impor- tant conversations aren't about isolated materi- als or heroic devices. They're about integration, and more specifically, about how ceramic-based RF packages and module architectures shape system-level behavior long before the signal ever reaches free space. At high frequencies, the package ceases to be a container. It is a participant. The Shift From Components to Ecosystems For much of electronics history, it made sense to think in terms of discrete building blocks. A component had a defined function where a package protected it, and a board connected it. BY C H A N D R A G U PTA , R E M T EC Performance was largely a matter of selecting the right parts and assembling them correctly. That mental model breaks down as frequency increases. At RF and microwave frequencies, es- pecially as we push into millimeter-wave, the boundaries between components, packages, and systems begin to dissolve. Parasitics stop being second-order effects. Thermal paths become sig- nal integrity decisions. Mechanical tolerances turn into electrical variables. In this environment, performance is emergent. It arises from interactions, not specifications. Ceramic-based RF packages sit where materials science, electromagnetic behavior, thermal man- agement, and manufacturability converge. The architectural decisions made here ripple outward, sometimes amplifying system performance, some- times quietly limiting it. Click here to read the full column When you do that, something interesting hap- pens: The signal stops reacting, reflecting, distort- ing, and fighting the path you've created. It simply moves and flows. That's really the point of controlled impedance design: not to perform engineering "black magic," but to create a path so consistent that the signal has no reason to do anything unexpected. I-CONNECT007 John Watson is a professor at Palomar College, San Marcos, California. To read past columns, click here. E L E M E N TA RY, M R . WATS O N