With the rapid advancement of 5G communications, autonomous driving radar, satellite communications, and high-speed data networks, traditional FR-4 PCB materials are facing performance limitations. As signal frequencies enter the GHz range and even millimeter-wave bands, a material called PTFE has become the preferred choice for engineering designers. So, what exactly is PTFE? And why does it stand out in this high-frequency race? I’m sure you will find answers after reading our article below.
I. What is PTFE?
PTFE , named polytetrafluoroethylene, commonly known as “Teflon,” is a high-performance fluoropolymer renowned for its exceptional chemical resistance, thermal stability, and non-stick properties. PTFE is not only extensively used in medical, food processing, and cookware industries (e.g., non-stick pans), but also serves as the premier substrate material for high-frequency circuit boards. Its outstanding electrical insulation, resistance to extreme temperatures (-200°C to +260°C), and environmental durability make it widely adopted in the PCB industry for manufacturing high-end circuit boards requiring high-frequency and high-speed performance.
II. PTFE’s Advantages in PCBs
1. Low Dielectric Constant (DK)
PTFE exhibits a dielectric constant of approximately 2.1±0.05, with minimal fluctuation of less than ±0.02 across the ultra-wide frequency band of 1–100 GHz. This is significantly lower than the dielectric constant of traditional FR-4 materials, which is around 4.5. PTFE is better suited for high-speed digital signals and high-frequency analog signals, minimizing signal delay and distortion to ensure rapid signal transmission.
2. Low Dielectric Loss Factor (DF)
Compared to FR-4’s DF value of approximately 0.02, PTFE’s loss factor ranges from 0.0002 to 0.002, dropping as low as 0.0005±0.0001 at 1GHz. This minimal signal loss ensures negligible energy dissipation during transmission, enabling extended reach and significantly reduced signal attenuation. This is crucial for enhancing the sensitivity and coverage range of communication equipment
3. High/Low Temperature Resistance
Unlike other materials that exhibit significant dielectric property changes under large temperature variations, PTFE maintains stable performance across a wide range from -200°C to 260°C. This stability prevents substrate deformation or performance degradation during high-temperature soldering in PCB manufacturing, meeting demands for high-temperature environments.
4. Low Moisture Absorption
PTFE exhibits moisture absorption below 0.01%, granting it exceptional moisture resistance. This advantage prevents moisture ingress into PCBs that could cause circuit short-circuits or component damage, significantly ensuring reliable PCB operation in high-humidity environments.
III: PTFE’s Challenges and Solutions
1. Challenges
1.1 High Cost and Low Yield Rate
PTFE laminates like ROGERS’ RT/Duroid series cost 20–50 times more than FR-4. Combined with low processing yield rates and significant material waste, this substantially increases manufacturing costs.
1.2 Complex Processing Techniques
1.2.1 Flexibility
Due to PTFE’s inherent softness, drilling during PCB fabrication often causes burrs and unevenness on hole walls. This affects subsequent through-hole plating processes and risks circuit breaks or open circuits. Specialized drill bits are required, as standard bits easily cause delamination.
1.2.2 High Thermal Expansion Coefficient
PTFE exhibits a thermal expansion coefficient approximately 5-6 times that of conventional materials. This causes substantial stress between PCB layers during high-temperature processes, leading to issues like copper foil delamination, layer misalignment, and drilling inaccuracies. These factors severely compromise the structural integrity of the PCB.
1.2.3 Poor Adhesion
PTFE’s inherent non-stick properties make solder mask adhesion difficult. Additional processes like plasma treatment or chemical etching are required to enhance bonding strength for proper copper foil integration. Inadequate treatment may cause solder mask layers to peel off during use, compromising the PCB’s insulation and protective capabilities.
2. Solutions
Jerico possesses mature PTFE processing expertise and specialized equipment. Our fully automated plasma treatment system, combined with CNC drilling parameters customized for PTFE and multi-stage vacuum lamination processes, ensures every PTFE PCB achieves exceptional hole-to-copper bonding strength, stable impedance control, and outstanding dimensional stability. This guarantees the reliability of the final product.
IV. Primary Application of PTFE PCBs
Due to its unique properties and core advantages such as ultra-low dielectric loss and wide-temperature stability, PTFE is primarily used in high-end electronic applications involving high-frequency, high-speed signals and extreme environments.
1.Satellite Communications/5G Base Stations: Examples include Massive MIMO antennas, power amplifiers, and filter products.
2. Aerospace and Defense: Examples include radar systems and satellite communication products.
3. Automotive Electronics: Examples include millimeter-wave radar products for intelligent driving, well-suited for adaptive cruise control and collision avoidance systems.
４．Medical Devices: Examples include MRI (Magnetic Resonance Imaging) equipment.
V. How to Determine PTFE Material Suitability?
Beyond the DK/DF values and application scenarios mentioned above, factors like signal frequency, data rate, and operating environment should also be considered. If your application requires signal frequencies exceeding 10 GHz, data rates surpassing 25 Gbps, and operation in extreme temperatures or high humidity, PTFE is your optimal choic
VI. Summary
With nearly 20 years of deep expertise in the PCB industry, Jerico excels in various board materials, post-processing, and assembly. We are your premier choice for PCB/PCBA solutions. Our passionate and professional service remains unwavering for our clients. Let’s explore and grow together.
