PCB Circuit Materials Selection and Its Influence in Different Frequency Bands of 5G

PCB Circuit Materials Selection and Its Influence in Different Frequency Bands of 5G

The 5G switchover will be an important decision for many industries, but the switchover will depend on their applications and operations. Some industries need to adopt the new technology quickly to remain competitive, while others may want to take their time. Regardless of which industry you are in, you should consider the potential costs associated with using new high-speed materials. Stack-up time for PCBs may increase significantly with high-speed materials, so it is worth taking your time to make the right decision.

Dielectric constant

When it comes to PCB material selection, the dielectric constant is an important consideration. It determines how quickly the material will expand and contract when exposed to a change in temperature. The thermal conductivity rate of PCB materials is typically measured in watts per meter per Kelvin. Different dielectric materials will have different thermal conductivity rates. Copper, for example, has a thermal conductivity of 386 W/M-oC.

When selecting PCB materials, remember that the effective dielectric constant of the substrate affects the speed of electromagnetic waves. The dielectric constant of the PCB substrate material and trace geometry will determine how quickly a signal can travel across the circuit.

The dielectric constant is a key consideration when selecting PCB materials for 5G networking. High permittivity will absorb electromagnetic signals and degrade the sensitivity of communications. Therefore, it’s crucial to choose PCB materials that have low permittivity.

Trace thickness

The frequency range of the 5G technology is larger than the previous wireless communication techniques. This means that shorter structures are susceptible to being excited by the signals. Typically, the wavelength of a single PCB trace is one centimeter. With this frequency range, a single trace can be a great reception antenna. However, as the frequency range broadens, the susceptibility of a PCB trace increases. Thus, it is essential to determine the best shielding approach.

The frequency bands of the 5G standard are divided into two parts – the low band and the high band. The first band is the millimeter-wave region, while the second band is below the 6GHz threshold. The band centered around 30 GHz and 77 GHz will be used for the mobile network.

The second band is low band, which is commonly used in the energy sector to communicate with remote wind farms, mining operations, and oil fields. It is also used to connect smart sensors in agriculture. Mid-band 5G, which transmits around 1.7GHz to 2.5GHz, provides a good balance between speed and coverage. It is designed to cover large areas and offer relatively high speeds, which are still faster than what you can get with home internet.


When it comes to manufacturing electronic products, the choice of materials for PCBs is critical. There are many challenges when manufacturing at high frequency bands, such as 5G. Fortunately, PCBA123 has created families of materials that meet the requirements for this new frequency range.

The higher carrier frequencies used in 5G networks will enable higher data rates and lower latency. This will allow for greater connectivity for a much larger number of devices. This means that 5G may well be the standard for the Internet of Things. However, as the frequency band increases, so too does the complexity of the devices.

Fortunately, there are some ways to reduce the cost of PCBs. For example, one option is to use low-loss liquid crystal polymers, which have a lower Tg. While this option can lower costs, it can introduce new permittivity concerns. Alternatively, manufacturers can use flexible ceramics and polyimides, which are better suited for low-temperature applications.

Thermal expansion

High-frequency PCB circuits require materials with different thermal expansion characteristics. While FR-4 is the most common material used in high-frequency circuits, there are also many other materials that can be used to minimize loss. Among these materials are pure polytetrafluoroethylene (PTFE), ceramic-filled PTFE, hydrocarbon ceramic, and high-temperature thermoplastic. These materials vary in Dk values, and the loss factor is based on surface contaminants, laminate hygroscopicity, and manufacturing temperature.

PCB circuit materials used in 5G technologies have to be resistant to higher temperature variations. Increasing thermal resistance will allow circuit boards to be processed using existing circuit board processing facilities. In addition, 5G technologies will require higher-quality PCB materials. For example, Isola MT40 is a material with a low coefficient of thermal expansion in the thickness direction, with a Dk/Df of 0.03, indicating that it is appropriate for high-frequency applications.

To ensure signal integrity, 5G systems will require high-speed and high-frequency components. With effective thermal management, these components can be designed to perform at the highest speed possible. Thermal conductivity, or TCR, is a property that measures the dielectric constant of a substrate in relation to temperature. When a circuit is under high-frequency operation, it generates heat and loses dielectric performance.

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