High frequency PCB are one of the widely used boards in the engineering world. These PCBs are known for their wide range of features and properties. PCBs are an integral aspect in the production of any electronics.
The use of a high frequency PCB can’t be underestimated. This circuit board has been used for the production of various electronics. In this article, we will be discussing important things you need to know about this PCB.
High Frequency PCB – What is it?
High frequency PCB transmit electromagnetic waves with minimal losses. This type of PCB is commonly utilized in applications where transmission of signals between objects is required. In the fabrication of a high frequency PCB, the use of specific materials is required.
This board features faster rates of signal flow. Its frequency range is about 100 GHZ. High frequency boards offer low levels of thermal expansion, lower DF, and lower DK. These circuit boards are commonly used for HDI technology.
Properties of High Frequency PCB
High frequency PCB offer a wide range of properties. Understanding these properties helps you to understand these PCBs. These printed circuit boards are called high frequency Boards because of the properties they offer. Let us have a look at the properties of these PCBs.
Dissipation factor: frequency PCB have a low dissipation factor which falls between 0.0019 and 0.025. This value helps to ensure that the signal transmission rate isn’t affected. Low dissipation factor also enables improved signal transmission. A lower dissipation factor can help to minimize signal loss.
Low and stable dielectric constant: The dielectric constant of a high frequency PCB is lower and stable. This helps to ensure frequency transmission. This also ensures less signal delay. Lower dielectric constant leads to higher rate of frequency transmission.
Chemical resistance: High frequency PCBs can withstand chemicals. These boards can survive chemical attack when exposed to one. Due to this property, these circuit boards are less likely to corrode.
Low moisture absorption: These PCBs have a low rate of water absorption. It doesn’t absorb moisture and as such, it can withstand a humid environment.
Low dimensional stability: frequency PCB feature low dimensional stability. These PCBs maintain their size irrespective of the temperature they are exposed to. Even when they are exposed to heat, their size remains the same.
Guidelines for Designing High Frequency PCB
PCB designers need to take some steps when designing high frequency PCB material. Below are steps that need to be taken;
Plan your design
Before you commence with the PCB design, it is vital you have a design in mind. Doing this will help you to prevent anything that might cause setbacks for your design. Having a checklist is an important way to go about this.
Determine the PCB signal frequency
Make sure you determine the voltage and power demands for the integrated circuits. Decide if you will be dividing any power planes. You also need to check if different signals can be accommodated. The manufacturer helps to ensure what the requirements for minimal tolerance are. It is important you have a plan of how to reduce the noise level on your high-frequency signals.
Draw up board stack up plan for production
Immediately you plan how to design the PCB, it is important to write down the demands for the stack up layer. You can seek the help of the manufacturer to know the specific material for your PCBs. It is important you understand the specific constraints and materials for your printed circuit board.
Plan the floor
When it comes to floor planning, you have to divide your PCB into sections. You need to determine if you will be placing your subcircuits into a bigger design. This is important when there are digital and analog sections that need to be carefully isolated to reduce interference.
Determine the power and ground planes
This is an important step. After you have defined the PCB layout, you need to examine your HDI PCB design. You need to understand the ground plane. You may not have to divide the ground plane using a routed signal.
Dividing the ground plane indicates that you need to rotate the void. This may influence the signal timings and EMI. Dividing the ground plane is necessary. Make sure a resistor is included along the signal trace. This will help the signal have a gap which enhances the return path.
Reduce the size of land patterns
High frequency PCBs often feature small pad. Their pads are smaller than that of other PCBs. Reducing the PCB space helps to ensure the PCB is useful. You can also maintain the pad size to match the component pins size.
Reducing space comes with several benefits. This will minimize the parasitic capacitance and increase the mechanical strength. If you reduce the space, there will be more space for various pairs.
Route the frequency signals
If you want to get more shielding benefits of this board, you need to route your frequency signals. High-frequency signals produce high radiation. There can be interference between two separate signals due to this. Routing the frequency signals can help you prevent this from happening.
Design a good current return path: For high frequency PCB, every signal needs a route. The route begins from the source ending at the sink via the path. Minimal obstruction is required by the path. This is an integral part of the design and fabrication of radio frequency substrates.
In some cases, you might need to utilize a via to make sure the path remains smooth. The currents will likely spread over divisions on your ground plane if you don’t do this.
Use 3W rule to reduce trace coupling: When it comes to signal integrity during transmission, line coupling may result in a serious challenge. The 3W rule will help you to reduce this. Applying this rule will ensure there is increase in the distance between the traces and as such, minimizing the coupling effect.
Apply 20H rule to reduce plane coupling: When there is coupling between ground and power planes it can be a threat to your PCB design. According to the 20H rule, you need to make sure the thickness between the adjacent power and ground plane is much thicker than the power plane.
Fabrication Process for High Frequency PCBs
The fabrication process of high-frequency circuit boards is a straightforward one. It is very easy to fabricate a PCB if you can understand some considerations.
Make a PCB design: This is the first thing you do. Here, you have to plan where the PCB blueprint will be placed. You can utilize Extended Gerber, designer software, to help with your design.
Print PCB design: Here, you print your PCB design. A plotter printer is used for printing. This printer produces a PCB film. This film has two ink types, the black ink and the clear ink. The clear ink shows the non-conductive areas of the PCB. The copper and the circuit of the board use the black ink.
Print copper for the inner layers: In this stage, the PCB manufacturing starts here. After printing the PCB on the laminate, the copper will be pre-bonded on the exact laminate that serves as the PCB structure. To unveil the initial PCB blueprint, the copper can be engraved.
Layers alignment: In high frequency PCB manufacturing, the layers have to be aligned. The holes can be used to arrange both the outer and inner PCB layers.
PCB layers lamination: Here, you laminate the PCB and the lay-up steps. Prepare the outer and inner layer and then join them. A metal clamp can help you join the layers.
Drilling: An X-ray machine can help you to determine the drilling spots. You can then drill holes to help secure the circuit board. The extra copper can be filed off after you complete drilling.
Plating of PCB: For PCB plating, you will need chemicals. These chemicals will help you sandwich the layers together. Ensure you clean the board before using different chemicals on it.
Solder masking: Here, the panel has to be cleaned before applying the solder mask. An epoxy ink and the solder film will be applied.
Screening and finishing of silk: The PCB will be either plated with HASL, silver, or gold. This will provide shielding to the copper and the pad. Silk screen the PCB after it has been plated.
Testing: To ensure your circuit board functions well, you are required to test it. The isolation and circuit continuity tests are an example of these tests.
Cutting: Once you have tested your PCB, you can make some cuts from your PCB panel. The PCB cutting can be done through a CNC machine or a V-a groove.
High Frequency PCB Applications
High frequency PCBs are used in various applications. These boards are specially fabricated to meet the requirements of high temperature applications. They are used in applications like;
Advanced communication system: These boards are used in the communication systems. They are commonly used in filtering devices, amplifiers, booster stations, and receivers.
Military industry: High frequency PCB materials are used in the production of ammunition and firearms.
Radar systems: These PCBs play a vital role especially in the marine and aviation industries. Radar systems prevent ships from obstacles like icebergs in marine application. The radar system guides aircraft and as such prevents accidents.
Medical systems: These boards are used in the manufacturing of medical electronics like monitoring and diagnostic devices.
Top 6 High Frequency PCB Manufacturers in 2023
High frequency PCBs refer to printed circuit boards designed to operate at high frequencies typically above 1 GHz. They are used in applications like telecommunications, aerospace and defense, satellites, automotive radars and more. High frequency PCBs enable the development of products and systems that need fast data speeds, high bandwidth and fast processing.
However, manufacturing high quality and reliable high frequency PCBs requires expertise and specialized capabilities. From substrate materials selection to fabrication processes, each step requires care and precision. As high frequency circuits operate at the cutting edge of speed and performance, there is little room for error.
In this article, we list the top high frequency PCB manufacturers of 2023 who possess the sophisticated technological capabilities to fabricate boards for high frequency applications.
Key Capabilities Needed for High Frequency PCBs
Some of the specialized capabilities needed for reliable high frequency PCB fabrication include:
- Dielectric materials – High frequency PCBs require dielectric substrate materials like Rogers, Taconic, Arlon with stable dielectric constants and low loss tangents.
- Impedance control – Maintaining strict impedance control across traces through precise manufacturing processes.
- High density interconnects – High density routing and spacing to create compact layouts.
- Embedded passives – Embedded resistors and capacitors integrated into the PCB for better performance.
- Signal integrity – Careful stackup design, layer sequencing, power plane management for signal integrity.
- EMI control – Shielding, containment solutions for electromagnetic interference (EMI).
- Thermal management – Effective thermal design to dissipate heat from high speed circuits.
- Testing – Extensive signal integrity and power integrity testing for reliability.
Let’s look at the top manufacturers providing these capabilities for high frequency PCB fabrication.
Top 6 High Frequency PCB Manufacturers in 2023
1. RayMing Technology
Founded in 2001, RayMing is an advanced PCB and high frequency PCB manufacturer based in China. With its cutting-edge manufacturing technologies and processes, RayMing specializes in producing complex, high density and high frequency PCBs.
Some key capabilities include:
- Wide material portfolio including Rogers, Taconic, Arlon, BT resins.
- Stackups with 16+ layers and 6 mil line/space.
- 1 oz copper to improve signal transmission.
- Captive fabrication for quality and security.
- Dedicated quickturn production lines.
- Extensive SI/PI simulation and modeling.
- IST and fixture testing for electrical performance.
- AS9100 quality management certification.
- MIL-PRF-31032 and MIL-PRF-55110 certifications.
From prototyping to volume production, RayMing delivers high quality, high frequency PCBs with short lead times. They offer one-stop prototyping within 24 hours and production lead times as fast as 3 days.
With advanced manufacturing capabilities and processes in place, RayMing produces complex high frequency boards from 1 GHz to 80+ GHz for industrial, military and aerospace applications.
2. Multi-CB
Multi-CB is a professional high-end PCB manufacturer based in China that specializes in producing high frequency PCBs. With over 500 skilled engineers and employees, they are highly focused on meeting the growing demands of 5G and high-speed technologies.
Key capabilities include:
- High layer count PCBs up to 32 layers.
- Line width and line spacing down to 3/3mil.
- 1 oz copper for high frequency applications.
- Excellent SI/PI design and simulation.
- Material expertise with Rogers, Taconic, Arlon.
- Quick-turn prototyping in 5 days.
- Comprehensive testing for electrical performance.
- Flex-rigid PCB manufacturing.
- ISO 9001 and IATF 16949 certified.
Multi-CB provides optimized high frequency PCB solutions ranging from RF boards, antenna boards to mmWave boards for 5G infrastructure. Their high-precision techniques enable cutting-edge routing densities.
3. Unimicron Technology
Unimicron is a global provider of high reliability PCBs and IC substrate manufacturing services. Founded in 1990, they offer advanced technology solutions for high frequency and high-speed PCBs.
Key strengths include:
- High layer count HDI boards up to 48 layers.
- Buildup MLBs with 6/6 L/S densities.
- Accurate thin core handling and drilling.
- Extensive modeling analysis.
- Signal integrity testing.
- Comprehensive quality control.
- IATF 16949 automotive certification.
- Cutting-edge facilities in Germany, Japan and China.
Unimicron provides advanced packaging substrates and RF/high frequency PCBs for aerospace, networking, and high-speed computing applications. Their global expertise in HDI, RF and flex-rigid technologies enable next-gen products.
4. TTM Technologies
TTM Technologies is a leading global PCB manufacturer providing time-to-market and high frequency PCB solutions. Their unique strengths include:
- Advanced RF materials expertise.
- Fabrication capabilities down to 2 mil lines and spaces.
- 1 oz copper and less than 3 mil dielectric.
- Modeling and simulation expertise.
- Signal integrity testing.
- Flexible and rigid-flex manufacturing.
- Facility clearance and security for defense work.
- Scale with 23 production plants globally.
TTM enables the development of high-performance systems for aerospace, automotive, telecom, and medical applications. Their vertical integration and rigorous HDI processes produce advanced RF/microwave boards up to 125 GHz.
5. Würth Elektronik GmbH
Part of the Würth Group, Würth Elektronik is a leading PCB producer focused on high-end technologies. Their strengths in high frequency PCBs include:
- Advanced RF materials including Rogers, Taconic, Arlon.
- Blind and buried vias with μ-via in pad.
- High layer count boards up to 30 layers.
- Line width/line spacing down to 100μm/100μm.
- Embedded passives for reduced parasitics.
- Dedicated microwave PCB line up to 80 GHz.
- Extensive characterization and test capabilities.
- Facilities in Germany and Asia.
Würth’s intensive R&D in new materials combined with their process innovations in HDI PCBs allows them to stay at the cutting edge of high frequency PCB fabrication. They offer high performance boards for communication, industrial and automotive radar systems.
6. AT&S
AT&S is a European high-end PCB manufacturer with a strong heritage of technology leadership in high frequency PCBs since the early 1990s. Key capabilities include:
- Advanced RF laminate expertise.
- Extremely high layer counts – up to 48 layers.
- Line width/line spacing down to 25μm/25μm.
- Buried vias and μvia-in-pad.
- SiP and embedded component integration.
- Rigorous testing and inspection regimes.
- Global facilities with proximity in Europe and Asia.
- Single-source solutions from design to volume mfg.
AT&S produces high-tech HDI, rigid-flex and high frequency PCB technologies for high reliability applications in mobile, automotive, industrial and medical sectors. Their expertise in RF materials and processes enables cutting-edge boards.
How to Select a High Frequency PCB Manufacturer
Here are some key considerations when selecting a high frequency PCB manufacturing partner:
- RF materials expertise – Look for experience with Rogers, Taconic, Arlon and other advanced dielectric materials.
- Manufacturing capabilities – Assess their line width/space, layer counts and other capabilities.
- Modeling, simulation and testing – RF modeling and signal integrity testing is crucial.
- Quality certifications – ISO, IATF16949 and AS9100 certifications.
- Technical support – Evaluate design, layout, material selection and modeling support.
- Prototyping abilities – Rapid prototyping services enable faster iteration.
- Scalability for volume – Manufacturing scale for verification builds and production.
- Customer references – Relevant experience and referrals in your industry.
Partnering with the right manufacturer enables the successful development and production of advanced high frequency PCBs for cutting-edge products.
Frequently Asked Questions about High Frequency PCBs
Here are some common questions about high frequency PCB technologies:
What are some typical applications of high frequency PCBs?
High frequency PCBs are used in products like radars, 5G equipment, satellites, defense electronics, test equipment, high speed computing, wireless infrastructure and automotive electronics.
What frequency range do high frequency PCBs support?
High frequency PCBs can range from 1 GHz to 80 GHz and beyond. mmWave boards operate from 30 GHz to 300 GHz.
What materials are used in high frequency PCBs?
RF laminates like Rogers RO3000, RO4000, RO1200, Taconic RF-35, Taconic TLY, Arlon CLTE-MW are typically used. They have stable dielectric constants and low loss.
What special considerations exist for routing high frequency PCBs?
Controlled impedance routing, minimal vias, proper ground plane usage, layer stackup, decoupling capacitors, thermal management and EMI containment are important considerations.
How are high frequency PCBs tested?
Testing focuses on signal integrity (eye diagrams, TDR) and power integrity (pdN/pdN, power supply rejection ratio) parameters. Fixtures are used for loaded testing.
Why are high frequency PCBs more complex to manufacture?
The very high speeds, RF behavior, critical tolerances, controlled impedances, special materials and importance of signal integrity introduce manufacturing and design complexity.
Partnering with an expert high frequency PCB manufacturer leveraging proven technologies and processes is key to ensuring reliable, high performance boards.
