Flex Circuit PCBs for 5G
In 5G applications, there will be a need to provide a lot of connectivity and data transfer. In order to meet this demand, PCBs will need to be designed to handle higher amounts of current and higher frequencies. In addition, there will be a need for more reliable connections. This is where flex circuits can help. Flex circuits are able to offer greater reliability than rigid PCBs, and they can be manufactured to fit the unique specifications of your application.
Flexible circuits use a polyimide or polyester base layer that is conductive copper and surrounded by an ultra-thin electrical dielectric covering. The resulting combination is flexible and durable, capable of withstanding mechanical shock and vibration. They also feature a smaller form factor and lighter weight than conventional rigid PCBs, making them an excellent choice for products that need to be compact or lightweight.
The material selection process for flex circuits is based on many factors including bending, temperature, chemical resistance and mechanical properties. The conductive copper layer of the flex circuit is typically between 0.0001 and 0.010” thick, while the dielectric layer can be as thin as 0.003”. Vapour deposition and adhesives are often used to attach the layers together.
Single-Sided Flex Circuits – These are the most common and simple flex circuits on the market, consisting of a single conductor layer on top of a flexible dielectric film. They are relatively inexpensive and easy to produce, and can be found in calculators for example.
Flex Circuit PCBs for 5G Applications
Double-Sided Flex Circuits – By printing on both sides of the dielectric film and connecting them with plated through holes, double-sided flex circuits offer enhanced power handling capabilities and high-density circuitry. They can be more expensive than single-sided flex circuits, but are an excellent option for applications that require greater flexibility and durability.
Rigid-Flex Circuits – By combining both rigid and flex substrates, this type of flex circuit offers the strength of rigid boards while still offering dynamic adaptability. They are often used as a replacement for point-to-point wire harnesses, reducing the number of connections in a design and minimizing points of failure.
In a recent webinar hosted by Epec Engineered Technologies, a comparison of the manufacturing processes involved in creating a rigid PCB and a flex circuit was provided. The rigid board required 8 steps to make, while the flex circuit pcb had 17. This is due to the fact that there are more steps and materials in creating a flex circuit.
While this information is helpful for understanding the difference in flex circuit cost between rigid and rigid-flex, it is still important to understand the specific needs of your product. For instance, if you are designing a flex circuit for an automotive product, it is critical to know the material properties of the flex circuit and how it will hold up in a harsh environment. This will enable you to accurately model the flex circuit’s tolerance to moisture, chemicals, heat, mechanical shock and vibration.
