Is it possible to design a simple flexible PCB with just a single copper layer?
Yes, it’s possible to single layer flexible PCB. However, some layout tools may assume a minimum of two copper layers by default. In that case, just note in your fabrication note that it’s a single-layer design, and only provide the Gerber for the copper layer you’re using and not the second layer.
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Certainly possible. This was a common way to connect cellular modules to a host board 20+ years ago. The bit that makes matters difficult is that it is really difficult to design it so that it is not going to become an EMC nightmare. If you have to go this way, the best plan to minimise the EMC impact is to reduce the “loop area” as much as possible. In practice this means putting return paths next to everything.
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Yes, designing a flexible PCB with a single copper layer is entirely feasible and commonly used in applications where simplicity and mechanical flexibility are key.
Beyond the tooling and fabrication, it’s important to consider the electrical implications. With only one conductive layer, you won’t have an internal ground plane or shielding, which can lead to EMI and signal integrity issues, particularly in high-frequency or fast digital designs. That’s why single-layer flex is best suited for low-frequency, analog, or basic digital signals. Proper grounding becomes critical and may require external shielding or careful routing to minimize loop areas.
On the mechanical side, single-layer flex boards are highly bendable, which is a huge benefit but only if traces are routed to avoid stress concentrations that could lead to failure over time.
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With single-layer flexible PCB, trace width becomes much more critical since you can’t distribute current across layers, so plan for wider power traces that affect overall cable width. The biggest challenge is component placement strategy since you can’t route around components with vias, making initial layout planning crucial. While single layer saves fabrication costs, you might need a physically wider flex for routing and sometimes narrow two-layer designs are actually cheaper depending on volumes and your fab house pricing.