F4BM245 DK2.45 PTFE fiberglass laminate manufacture 2-layer PCB with ED copper foil

Product Description

1. Introduction to F4BM245

F4BM245 is a high-performance PTFE fiberglass laminate manufactured by Taizhou Wangling Insulation Material Factory. It is produced through a scientifically formulated process combining fiberglass cloth, polytetrafluoroethylene (PTFE) resin, and PTFE film under strict processing controls. Compared to the earlier F4B series, F4BM245 delivers significantly improved electrical performance, including lower dielectric loss, higher insulation resistance, and enhanced stability, making it a reliable replacement for similar foreign products. 

 

The F4BM series offers a wide range of dielectric constants from 2.17 to 3.0, with customizable Dk options available. F4BM245 specifically features a dielectric constant of 2.45, striking an optimal balance between low loss, dimensional stability, and cost-effectiveness.

 

 

Copper Foil Options

The F4BM and F4BME variants share the same dielectric layer but differ in copper foil selection:

Variant	Copper Foil Type	Key Characteristics
F4BM245	ED (Electrodeposited) Copper	Suitable for applications without PIM requirements; cost-effective
F4BME245	Reverse-Treated Foil (RTF) Copper	Excellent PIM performance (≤ -159 dBc); more precise line control; lower conductor loss

 

By precisely adjusting the ratio between PTFE resin and fiberglass cloth, Wangling achieves accurate dielectric constant control while maintaining low loss and enhanced dimensional stability. Higher Dk values correspond to higher fiberglass content, resulting in improved dimensional stability, lower CTE, better temperature drift performance, and a slight increase in dielectric loss.

 

 

2. Key Technical Specifications (F4BM245)

Property	Test Condition	Unit	F4BM245 Value
Dielectric Constant (Typical) @ 10 GHz	10 GHz	—	2.45
Dielectric Constant Tolerance	—	—	±0.05
Dissipation Factor (Typical) @ 10 GHz	10 GHz	—	0.0012
Dissipation Factor (Typical) @ 20 GHz	20 GHz	—	0.0017
Thermal Coefficient of Dk	-55°C to +150°C	ppm/°C	-120
Peel Strength (F4BM – 1 oz ED)	—	N/mm	>1.8
Peel Strength (F4BME – 1 oz RTF)	—	N/mm	>1.6
Volume Resistivity	Normal State	MΩ·cm	≥6×10⁶
Surface Resistivity	Normal State	MΩ	≥1×10⁶
Electrical Strength (Z-direction)	5 kV, 500 V/s	kV/mm	>25
Breakdown Voltage (XY-direction)	5 kV, 500 V/s	kV	>32
CTE – X axis	-55°C to +288°C	ppm/°C	20
CTE – Y axis	-55°C to +288°C	ppm/°C	25
CTE – Z axis	-55°C to +288°C	ppm/°C	187
Thermal Stress	260°C, 10s, 3 cycles	—	No Delamination
Moisture Absorption	20±2°C, 24 hours	%	≤0.08
Density	Room Temperature	g/cm³	2.22
Long-Term Operating Temperature	—	°C	-55 to +260
Thermal Conductivity (Z-direction)	—	W/(m·K)	0.3
PIM Value (F4BME only)	—	dBc	≤ -159
Flammability	—	UL-94	V-0
Material Composition	—	—	PTFE + Fiberglass Cloth

 

 

3. Features & Benefits

F4BM245 delivers a compelling combination of performance advantages for high-frequency circuit designs:

 

Wide Dk Range (2.17 – 3.0): Selectable and customizable dielectric constants to meet diverse design requirements.

 

Low Dissipation Factor: Ultra-low loss of 0.0012 @ 10 GHz ensures high signal integrity and minimal insertion loss.

 

F4BME Option with RTF Copper: Delivers excellent PIM performance (≤ -159 dBc) , precise line control, and reduced conductor loss for demanding RF applications.

 

Dimensional Stability: Optimized PTFE-to-fiberglass ratio provides excellent dimensional stability and low thermal expansion.

 

Low Moisture Absorption (≤0.08%): Maintains stable electrical properties in humid environments.

 

Radiation Resistance & Low Outgassing: Suitable for aerospace and space applications.

 

UL 94 V-0 Flammability Rating: Meets stringent safety requirements.

 

Cost-Effective: Commercial-grade, high-volume production with excellent price-to-performance ratio.

 

Versatile Sizes: Multiple standard and custom panel sizes available to optimize material utilization and reduce costs.

 

 

4. Custom 2-Layer PCB Solution on F4BM245

Leveraging the advanced properties of F4BM245, we offer the following precision-engineered 2-layer rigid PCB solution. This design is ideal for RF, microwave, radar, and satellite communication applications requiring excellent electrical performance and mechanical stability.

 

 

PCB Construction Details

Parameter	Specification
Base Material	Wangling F4BM245 (ED Copper)
Number of Layers	2
Finished Board Size	100 mm × 80 mm (±0.15 mm)
Finished Board Thickness	0.6 mm
Minimum Trace / Space	4 / 5 mils
Minimum Hole Size	0.3 mm (through-hole only; no blind vias)
Outer Layer Copper Weight	1 oz (35 μm)
Via Plating Thickness	20 μm
Surface Finish	Immersion Gold (ENIG)
Top Silkscreen	None
Bottom Silkscreen	None
Top Solder Mask	None
Bottom Solder Mask	None
Electrical Testing	100% prior to shipment
Accepted Quality Standard	IPC-Class-2
Artwork Format	Gerber RS-274-X
Global Availability	Worldwide shipping

 

 

Design & Manufacturing Highlights

 

Optimized Thickness: The 0.508 mm (20 mil) core provides an ideal balance between mechanical rigidity and electrical performance for microwave designs.

 

Fine-Feature Capability: Supports 4/5 mil trace/space and 0.3 mm micro-vias, enabling dense, high-frequency circuit layouts.

 

Low-Loss Copper Layers: 1 oz (35 μm) ED copper on both sides provides excellent conductivity for RF signal transmission.

 

Reliable Interconnects: The Immersion Gold surface finish ensures a flat, oxidation-resistant, and highly solderable surface, supporting robust component attachment.

 

Excellent PTH Reliability: With 20 μm via plating and controlled Z-axis CTE, the PCB offers reliable plated-through-hole integrity.

 

Strict Quality Control: Every board undergoes 100% electrical testing and is manufactured to IPC-Class-2 standards, guaranteeing consistent quality and performance.

 

 

5. Typical Applications

F4BM245 is extensively used across a wide range of RF and microwave applications:

 

Microwave, RF & Radar Systems: High-frequency signal processing modules.

 

Phase Shifters: Precise phase control for beamforming and phased arrays.

 

Power Dividers, Couplers & Combiners: Power distribution and combining networks.

 

Feed Networks: Signal distribution for antenna arrays.

 

Phase-Sensitive Antennas & Phased Array Antennas: Stable phase performance for radar and communications.

 

Satellite Communications: Spaceborne and ground-based satellite equipment.

 

Base Station Antennas: Mobile communications infrastructure.

 

 

6. Conclusion

As a specialized supplier of custom high-frequency circuit boards, we combine the proven performance of Wangling F4BM245 – a commercially available, high-volume PTFE fiberglass laminate with excellent electrical and mechanical properties – with our precision manufacturing capabilities to deliver world-class PCB solutions. Our 2-layer offering fully leverages F4BM245's stable dielectric properties, low loss, dimensional stability, and cost-effectiveness, ensuring your RF and microwave designs achieve optimal performance and reliability.

 

 

Whether you are developing radar systems, satellite communications equipment, phased array antennas, or base station infrastructure, our engineering team is ready to support your project. For technical consultations, samples, or volume orders, please contact us today. We look forward to being your trusted partner in high-frequency innovation.