High frequency PCBs enable applications like 5G, WiFi, radars, etc, but face signal integrity issues. Learn key considerations for high frequency PCB design including managing loss, interference, stackup and more to aid complex communication, computing and electronics applications.
High Frequency PCB Design Considerations
High frequency PCBs refer to printed circuit boards designed to operate effectively at high frequencies typically above 1GHz. They facilitate functions like high-speed data transmission and wireless communication in products like smartphones, computers, base stations and more. But signal integrity issues tend to arise at such frequencies, so specialized high frequency PCB design is required for these high frequency PCB applications.
Typical Applications Suitable for High Frequency PCBs
Some common application areas well-suited for high frequency PCB implementation include:
- 5G NR/LTE cellular communication boards in smartphones
- WiFi/Bluetooth PCB modules in laptops, tablets and other handheld devices
- Automotive driver assistance system and autonomous driving PCBs
- Satellite communication and maritime radar boards
- Aerospace/defense electronic countermeasure system PCBs
- High Frequency PCB Design Challenges
Catering to such high frequency PCB applications brings about greater design and fabrication difficulties to manage signal loss and interference. Some key challenges are:
Signal Loss
At microwave frequencies, conduction losses are higher in thinner PCB traces, necessitating larger trace sizes for high frequency PCB applications. Dielectric losses also increase, converting signal energy into heat. Careful material selection and stackup design helps counter signal loss.
Signal Interference
Hi-speed signals can interfere with each other or get distorted by noise. Judicious component placement and routing with adequate spacing and isolation helps mitigate interference. Proper layer stack arrangements also play a key role.
How do you avoid high frequency interference in high frequency PCB applications?
Strategies like optimal component placement, employing ground planes, shielding high-speed traces, and adding filters or guard traces help control interference for high frequency PCB applications. Maintaining track symmetry and minimizing discontinuities and abrupt bends in routing helps too. Simulations identify problem areas early.
What are high-speed signals in PCB?
Generally signals above 100MHz to 3GHz range are considered high-speed. They require impedance control and termination techniques to prevent signal reflection issues. High signal rise times make them more vulnerable to radiation and crosstalk. High density interconnects handling multi-Gbps speeds also qualify as high-speed signals, pushing PCB design complexity.