F4BM265 Double-sided copper clad laminate DK 2.65 PTFE RF Circuit Board with 1oz Bare Copper

F4BM265 Copper Clad Laminate: A Tunable, High-Performance Substrate for Demanding RF Applications

The F4BM265, part of the F4BM/F4BME series from Taizhou Wangling Insulation Material Factory, is a PTFE (polytetrafluoroethylene) and woven glass fabric reinforced laminate engineered to provide a robust and customizable foundation for high-frequency circuit design. By precisely adjusting the ratio of low-loss PTFE resin to glass cloth, this material achieves a stable mid-range dielectric constant (Dk) of 2.65, offering designers an optimal balance between signal propagation speed, impedance control, and physical stability for a wide spectrum of RF and microwave applications.

This material series distinguishes itself through its dual cladding strategy. The F4BM265 variant utilizes standard Electrodeposited (ED) copper foil, making it a cost-effective and high-performance choice for applications where ultra-low Passive Intermodulation (PIM) is not a critical requirement. It delivers excellent electrical properties, including low loss (Df of 0.0013 @ 10 GHz) and high insulation resistance, ensuring efficient signal transmission and reliability. The material is formulated for enhanced dimensional stability and thermal performance compared to its predecessor, F4B, with a very low moisture absorption rate and a UL 94 V-0 flammability rating for commercial safety compliance.

The F4BM265 is specifically designed to thrive in challenging environments, featuring excellent resistance to radiation and low outgassing, which makes it suitable for aerospace and satellite applications. Its high glass fabric content at this Dk level contributes to improved dimensional stability, a lower in-plane coefficient of thermal expansion, and better thermal stability, supporting the manufacturing of reliable, high-density multilayer boards.

F4BM Data Sheet

Electrical Properties:

• Dielectric Constant (Dk) @ 10 GHz: 2.65 ±0.05
• Dissipation Factor (Df): 0.0013 @ 10 GHz, 0.0019 @ 20 GHz
• Thermal Coefficient of Dk (TCDk): -100 ppm/°C (-55°C to 150°C)
• Volume Resistivity: ≥ 6 x 10⁶ MΩ·cm
• Surface Resistivity: ≥ 1 x 10⁶ MΩ
• Dielectric Strength (Z-direction): > 25 KV/mm
• Breakdown Voltage (XY-direction): > 34 KV

Thermal & Physical Properties:

Coefficient of Thermal Expansion (CTE):

• XY-direction: 14-17 ppm/°C (-55°C to 288°C)
• Z-direction: 142 ppm/°C (-55°C to 288°C)
• Thermal Conductivity (Z-direction): 0.36 W/(m·K)
• Long-term Operating Temperature: -55°C to +260°C
• Moisture Absorption: ≤ 0.08%
• Density: 2.25 g/cm³
• Flammability: UL 94 V-0

Mechanical Properties:

Peel Strength (with 1 oz. ED Cu): > 1.8 N/mm

Thermal Stress Performance: No delamination after 3 cycles of 10s at 260°C

Cladding: Standard Electrodeposited (ED) Copper Foil.

Available Copper Weights: 0.5 oz (18µm), 1 oz (35µm), 1.5 oz (50µm), 2 oz (70µm).

Standard Panel Sizes: Includes 460 x 610 mm, 500 x 600 mm, 850 x 1200 mm, 914 x 1220 mm, and 1000 x 1200 mm.

Standard Thickness (Dielectric Core): A wide range from 0.1 mm (minimum for Dk ≤ 2.65) up to 12.0 mm, with corresponding tolerances.

Metal-Clad Variants: Available as aluminum-base (F4BM265-AL) or copper-base (F4BM265-CU) laminates for enhanced heat dissipation or electromagnetic shielding.

In summary, the F4BM265 stands out as a versatile, high-value substrate that delivers consistent mid-range dielectric performance, excellent thermal reliability, and significant manufacturing flexibility. Its broad availability in various thicknesses, panel sizes, and specialized configurations like metal-core boards makes it an adaptable and economical solution for power dividers, couplers, feed networks, phased array antennas, and satellite communication systems across commercial, defense, and aerospace markets.