Printed circuit boards (PCBs) are the backbone of every electronic device, facilitating electrical connections and carrying various signals. With the advent of 5G technology, PCBs must meet new demands and requirements. The large-scale deployment of 5G networks will compel designers to rethink PCB designs for mobile, IoT, and telecommunications devices. The 5G network, characterized by high speed, wide bandwidth, and low latency, necessitates meticulous PCB design to support these high-frequency features.

5G Challenges for PCB Design

Compared to 4G, 5G technology offers significantly higher transmission rates, traffic density, and connections per square kilometer. The 5G network aims to provide 1 millisecond latency, operating on a much wider frequency range. This means PCBs must support data rates and frequencies far higher than current ones, pushing mixed signal design to its limits. While 4G operates below 6 GHz, 5G will extend into the millimeter wave region (mmWave), with bands around 26 GHz, 30 GHz, and 77 GHz.

The use of the Extremely High Frequency (EHF) band presents one of the most challenging aspects of 5G PCB design. Millimeter waves propagate only by line-of-sight and are strongly attenuated by obstacles like buildings and foliage. This necessitates more base stations and multiple phased array antennas to support advanced 5G features like beamforming. Both mobile devices and base stations will require PCBs integrating multiple Antenna Array Units (AAU) with extensive use of Massive MIMO technology.

Key Considerations for 5G PCB Design

Designing a 5G circuit board involves managing mixed high-speed and high-frequency signals. The choice of materials is crucial to prevent power losses and ensure signal integrity. Materials with very low dielectric transmission loss and high thermal conductivity are essential, especially for frequencies above 6 GHz. The substrate must adapt to the special requirements of the millimeter wave frequency band.

Material Selection: Choose materials with a low dielectric constant (Dk) to minimize losses, as Dk losses increase with frequency. Use minimal soldermask, as high moisture absorption can lead to significant losses. Ensure copper traces and planes are perfectly smooth to reduce resistive losses, as the current skin depth is very shallow at high frequencies.

5g circuit board

Signal Integrity: High frequencies pose significant challenges for signal integrity. High-density interconnections (HDI) require thinner tracks, which can degrade signals and cause losses. Impedance control is critical, and traditional PCB manufacturing processes may not suffice. The mSAP (Semi-Additive fabrication Process) technique can create precise trace geometries, improving impedance control and signal integrity.

PCB Geometry: The geometry of the PCB, including laminate thickness and transmission line characteristics, plays a fundamental role. The laminate thickness should be between 1/4 and 1/8 of the highest operating frequency’s wavelength. Transmission lines can be microstrip, stripline, or grounded coplanar waveguide (GCPW). Each has its pros and cons, with GCPWs offering higher conduction losses but being an excellent choice for high-frequency applications.

Automatic Inspection: High-frequency PCBs require automatic inspection procedures, both optical (AOI) and through Automated Test Equipment (ATE). These procedures enhance product quality by identifying potential errors or inefficiencies. Advances in automatic inspection and testing have led to significant time savings and reduced costs, ensuring consistent performance with high production rates.

Conclusion

The introduction of 5G technology imposes new demands on PCB design, requiring careful consideration of materials, signal integrity, and geometry. HUlHE Circuits is at the forefront of this technological shift, providing innovative solutions for 5G circuit boards. By leveraging advanced materials and manufacturing techniques, HUlHE Circuits ensures that their 5G PCBs meet the stringent requirements of high-speed, high-frequency applications.

For more information about custom pcb china, please feel free to contact us!