As the world moves from 4G to super-fast 5G networks, the need for advanced printed circuit boards is now more critical than ever. The 5G PCB has to cope with higher frequency situations, which calls for special features than the traditional circuit board. Here, we explain the challenges that face 5G PCB design and the rules that govern its production process.
What is a 5G PCB?
5G PCB is a type of board designed with special features to ensure the optimal operation of 5G communication systems. The 5G board has higher-level specifications than the traditional printed circuit board.
These include advanced heat dissipation systems, optimized traces, and EMI reduction parts, among other requirements such as proper material selection. But what is 5G in the first place?
5G (or fifth-generation technology) is best defined as upgrading 4G networks and the latest advancement in wireless systems. 5G networks operate at extremely high frequencies—with wavelengths in the mm range—and offer today’s highest data transfer rates.
For example, 5G speeds can go up to 20Gbps, which surpasses those of 4G networks by between 10 and 20 times. But that also means specialized hardware is needed to support the higher requirements. Most notably, this refers to the need for a unique type of circuit board called the 5G PCB.
The 5G PCB is named for having features uniquely designed to support the higher dater rates and the extremely high-frequency levels of 5G communication systems. These include everything from the thickness of the board and its raw materials to the design of copper traces and other characteristics.
As such, proper considerations must be made at all stages of the board’s production process, especially the design phase. The section below examines the most essential requirements for the 5G circuit board design process.
5G PCB Design
5G networks, being the demanding systems they are, require specialized printed circuit boards to operate effectively. THEREFORE, 5G PCB design is a critical process that requires proper planning and expertise. To narrow that down to the specifics, designers must ensure the following when creating a PCB with 5G requirements.
The 5G board is meant to handle high-frequency signals. That means a lot of energy being lost in the form of heat. Therefore, selecting a suitable material that can dissipate heat is the first requirement when designing this type of circuit board.
So, a substrate with high thermal conductivity is preferred. Ideally, that means exploring different materials than the standard FR4, including flexible and non-flexing substrates.
In addition to thermal conductivity, a 5G PCB substrate must have a dielectric constant value that is as low as possible. That’s because dielectric losses are higher at higher frequencies, affecting the board’s performance when used in 5G applications.
The traces’ length, width, and spacing must be carefully considered during 5G PCB design. The traces should be made as short as possible to minimize losses. Their width and spacing should be correctly measured to keep impedance constant and signal distortion low.
Besides track size and spacing, their surfaces must remain smooth. Irregular or uneven conductor surfaces increase resistive losses by causing a decrease in the phase velocity of the circuit board signals.
This, among other things, means a change in the way that the 5G board is manufactured. For example, the sub-additive process is recommended when the aim is to maintain copper trace geometry and precision in these high-speed PCBs.
EMI, or electromagnetic interference in full, is a severe concern when it comes to 5G printed circuit boards. That’s because with higher frequencies comes increased levels of electromagnetic radiation, and this can affect the integrity of signals, leading to data loss and other effects.
During the 5G PCB design process, mitigation measures must be taken. These include proper EMI shielding techniques such as shielding cans and gaskets, using ground planes, and correct component placement. EMI filtering parts may also be employed.
5G PCB Design Rules
Several rules apply when designing and manufacturing printed circuit boards for use in 5G systems, such as the 5G PCB antenna, power amplifier, and so on. The most crucial of these rules, which are meant to meet the unique needs of highly high-speed boards, include the following.
1. When designing a 5G circuit board, ensure materials that will not quickly decay or get damaged by delamination or peeling traces when subjected to high temperatures.
2. Use a laminate whose thickness is ¼ to ⅛ of the wavelength of the specific 5G PCB’s highest frequency. This is to avoid signal distortion that may occur if the laminate is too thin or too thick.
3. Minimal solder masks are recommended for the 5G PCB. That’s because solder masks can attract moisture in high humidity conditions.
Excessive moisture would cause changes to the specified values for the substrate’s dielectric constant and dissipation factor, leading to a lowered performance of the transmission lines.
4. Besides the mentioned considerations when designing a 5G board, importance must be put in the latter stages of its manufacturing process.
For example, because of their unique requirements, a 5G board is best inspected using automated equipment such as AOI. This ensures their higher quality and helps meet the higher requirement of 5G technology products.
The 5G PCB is a special circuit board requiring specific considerations while designing or making it. In addition to its unique requirements for high-speed and high-frequency signals, this type of board must be made within the industry rules for 5G applications. That means a lot for PCB manufacturers and those looking for circuit boards to use in 5G products or networks.