Considerations for High Frequency PCB Design

High-frequency PCB design requires a completely different set of knowledge compared to simple low-speed analog design or digital circuits design. Ignoring some of these practices may make the design be highly susceptible to EMI or cause signal loss. We here list some considerations for you when design a high frequency PCB.

1.Impedance MatchingImpedance matching is a key factor in high-frequency PCB design. As the frequency increases, the tolerance becomes lesser. Therefore, the designer needs to ensure that the impedance matches at the specified value.

2.Material SelectionUnlike low-speed or frequency designs, material selection is critical for a high-frequency PCB design. FR-4 here is not the best choice, because it can not achieve consistent dielectric constant of the PCB which is required by high-frequency design. This can lead to unacceptable signal losses in a high speed design.Instead, the ideal material for high-speed designs should have a much lower loss dissipation factor than the FR-4. In high-frequency design, even the slightest moisture of the PCB can affect the circuit itself. It is important to use a low moisture absorption material like PTFE.

3.Minimal SoldermaskYou may have chosen a suitable substrate for high-frequency design. But if you do not pay attention to the thickness of the solder mask, your design will still suffer from signal loss. Solder mask has a high moisture absorption rate, and wet solder mask is not suitable for high-frequency transmission.

4.Return LossReturn loss for a high-frequency design must be kept to the minimum. Since high-frequency signals use the least-inductive path, there should be no discontinuity in the ground plane below the signal traces themselves. Otherwise, high-frequency signals will use other non-ideal return paths, such as the power supply plane, and may cause ringing or reflections.

Order From Best High Frequency PCB Supplier

You should take enough time to evaluate different HF PCB suppliers to ensure you can find the best. A reliable supplier will make timely use of your product, which will make it easy to resell to all your potential customers. If you plan to use them, you’d better evaluate different high frequency PCB products to determine if they work well in your product. Some tips you should consider for you to find a best HF supplier include the following:

Cost Different high-frequency PCB suppliers offer different prices. Compare product prices from different suppliers is necessary when determining your HF supplier. Suppliers who sell products online are best for your consideration because it is easy to compare online prices. If there are hidden charges, then you need to consider the charges carefully.

Management and Quality Control SystemThis is crucial to your design because a leading high-frequency PCB supplier can contribute to the quality performance and market reputation of your product. You need a factor-finding audit to them to make sure you have confidence with the supplier.

Technology CapabilityThis is one of the basic factors you should consider. If the supplier is able to match your technical requirements then you can get your design work and function properly. Otherwise, your time will be much wasted.

The Reputation of HF PCB SupplierYou can read comments and options from other customers before continuing to order. For example, reading reviews makes it easy to know if a given supplier can offer the top-quality product. Buy products from the supplier with good reputation will keep your project run smoothly. The supplier will avail the products in good time for you to continue with your operations.

High Frequency PCB Specifications

High frequency PCB boards are highly needed in satellite communications such as satellite framework and cell phone getting base station. Key elements of high frequency PCBs are as following:

a.Dielectric constant should be small and stable enough, ordinarily the littler the best, high dielectric constant may prompt sign transmission delay.

b.Dissipation factor should be small, which for the most part influences nature of flag transmission, the littler dissipation factor could make littler flag wastage as needs be. 

c.The warm expansion rate should be the same as the copper thwart, but it is reasonable to expect that this distinction will prompt copper to be isolated in cold and warm processes.

d.Low water absorption; high water absorption will affect dielectric constant and factor in the wet condition.

In general, high frequency can be characterized as recurrences above 1 GHz. Currently, polytetrafluoroethylene (PTFE) materials are commonly used as part of high-frequency PCB production, it's likewise called Teflon, whose recurrence is ordinarily over 5GHz.. Similarly, FR4 or PPO substrates can be used for project between 1GHz and 10GHz. The three high frequency substrates have the following comparisons:

As to cover cost among FR4, PPO and Teflon, FR4 is the cheapest, while Teflon is the most expensive. Teflon is at its best in terms of dielectric constant and factor, water retention and recurrent. When product applications require repetitive frequencies more than 10 GHz, Teflon PCB substrates is a good choice for production. 

Obviously, Teflon is much better than other ones since the Teflon substrate has the solidness and warmth opposing property work, countless or fiber glass as the filling material.