Issue link: https://iconnect007.uberflip.com/i/1496727
40 DESIGN007 MAGAZINE I APRIL 2023 • Select material properties of PCB board and layer stackup arrangements to ensure minimal loss of precious RF wireless signals to optimize performance. Shaughnessy: What sort of problems do designers face in the RF arena that they don't see with typical PCB designs? Based on these differences, we can see that RF PCB design is not just designing intercon- necting traces to fit onto a board. We must also consider how RF signals are protected from interference from non-RF sections on the same board and propagated along RF trans- mission lines such as co-planar waveguides (CPW) or microstrips with careful shaping of transitions and bends to prevent signal reflec- tion and insertion loss. RF PCB design minimally requires simu- lation of critical RF signal paths for loss and unwanted coupling from neighboring non-RF components and traces. It is important for the RF PCB designer to understand how to simu- late and optimize critical RF paths on a mixed- signal board. Many of today's devices have multiple RF points—Wi-Fi, Bluetooth, GPS, and cellular. How can designers ensure that these signals "play nicely" together? Designers need to understand the antenna characteristics and where to locate the anten- nas for these signals on the PCB board to sat- isfy these prioritized requirements: • Antenna efficiency and impedance matching Figure 1: Examples of multilayer mixed-signal RF PCB simulations generated by a Keysight UXA signal analyzer utilizing Keysight RFPro software. Note that the critical RF paths traverse 14 layers of the PCB. The design data was input in the OBD++ format.