What is High Frequency PCB ?

High-frequency printed circuit boards (PCBs) play a crucial role in various advanced applications where signals operate at frequencies above 1 GHz. These PCBs have specific requirements and parameters that must be carefully considered during the design process to ensure optimal performance. Here are some key aspects to keep in mind when designing high-frequency PCBs:

Parameters To Consider For High-Frequency PCB Design:

High-frequency PCBs typically operate above 1 GHz, with applications in radar systems, military equipment, aerospace, telecommunications, and high-speed digital systems.

The dielectric constant of the PCB material affects the propagation speed of signals. Lower Dk values are preferred for high-frequency applications to minimize signal distortion and ensure accurate signal transmission.

Df represents the loss of signal energy as it travels through the PCB material. Lower Df values are desirable for high-frequency PCBs to reduce signal attenuation and maintain signal integrity.

CTE is crucial for high-frequency PCBs as it impacts the stability of the board’s dimensions under temperature variations. Low CTE materials help prevent issues like warping or delamination.

High-frequency PCB designs must minimize signal reflections, crosstalk, and electromagnetic interference (EMI) to preserve signal quality and reliability.

Design Considerations For High-Frequency PCBs:

Stackup Design

Optimize the layer stackup to achieve controlled impedance and minimize signal distortion. Consider using multiple ground and power planes for better signal integrity.

Routing And Layout

Keep signal traces short and direct to reduce signal loss and interference. Use differential pairs for high-speed signals and maintain proper spacing between traces.

Grounding

Implement a solid ground plane to provide a low-impedance return path for signals and reduce electromagnetic interference.

Component Placement

Place critical components strategically to minimize signal path lengths and reduce parasitic effects.

Material Selection:

Rogers Corporation

Rogers is a leading producer of printed circuit materials for high frequency applications in aerospace, defense, automotive radar and wireless communications. Popular microwave laminates from Rogers include:

  • RO3003TM – Glass microfiber filled PTFEsubstrate with low Dk and Df
  • RO4350BTM – Woven glass reinforced, ceramic-filled laminate with high dielectric constant
  • RT/duroid® 6002– Ceramic filled PTFE material with tight Dk and Df tolerances
  • RO4835TM – Glass microfiber filled, ceramically loaded laminate
  • TMM® 10i – Woven glass reinforced, ceramic-filled PTFE material
Taconic

Taconic manufactures a broad range of RF laminates including:

  • TLY-5TM – Low loss thermoset laminate for analog circuits

  • TLC-30TM – Low Dk glass microfiber PTFE composite
  • RF-35TM – Ceramic filled PTFE material for broadband applications
  • RF-60TM – Thin filmceramic filled fluoropolymer laminate
  • TacPreg® – Low loss thermoset prepregs available in various Dk
Isola

Isola offers high performance copper clad laminates including RF materials:

  • IS680– Low Dk glass weave reinforced laminate

  • FR408HR– High performance FR-4 with tight dielectric tolerance
  • P96 – High thermal reliability FR4 material
  • Getek® – Glass microfiber reinforced fluoropolymer substrates
  • ISOLA Astra MT77– Composite material for broadband applications
Arlon

Arlon specializes in high performance laminates for microwave and thermal management applications:

  • CLTE-XT– Low Dk glass reinforced hydrocarbon ceramic laminate
  • CLTE-AT– Glass reinforced PTFE composite material
  • 55NT– Non-PTFE, thermoset microwave substrate
  • 25N – Economical woven glass reinforced laminate
Park Electrochemical

Park Electrochemical provides NelsonicTM RF/microwave laminates including:

  • N9000-13EP – Tight tolerance woven glass reinforced substrate
  • N9000-13SI – Filled ceramic PTFE composite material
  • N9120-4 – High frequency laminate with PPS thermoplastic reinforcement