2. Specifications & Manufacturing Features

1. Hybrid High-Frequency Stackup: Integrated 3mm F4BM265 core substrate, S1000-2MB prepreg and 0.5mm S1000-2M dielectric material, achieving a total pressed thickness of 4.14mm
2. Uniform Layer Copper Thickness: 35μm finished copper thickness applied equally to all four layers for balanced signal transmission and current carrying capacity
3. Precision Circuit Design: Supports customized impedance control and blind via fabrication, meeting high-density and high-precision microwave circuit layout demands
4. High-Reliability Hole Plating: 25μm hole copper thickness manufactured per IPC-Class-3 standard, enhancing hole wall integrity and anti-fatigue performance
5. Dual-Side Surface Treatment: Blue solder mask with white silkscreen on both top and bottom sides for clear identification and comprehensive circuit protection
6. Premium ENIG Surface Finish: Improves corrosion resistance, solderability and assembly repeatability for industrial-grade long-term service
7. Stable Batch Consistency: Commercialized mass-production process with outstanding cost-performance for high-frequency RF project iteration

3. Advanced PCB Stackup Structure

This 4-layer hybrid high-frequency PCB adopts a scientific composite stackup structure combining F4BM265 low-loss PTFE substrate and S1000-2M standard dielectric materials. The layered collocation optimizes high-frequency signal performance while maintaining excellent mechanical rigidity and processing feasibility, perfectly adapting to impedance-controlled microwave circuit designs.

1. Layer 1: 35μm Finished Copper
2. Dielectric: S1000-2MB Prepreg + 0.5mm S1000-2M Substrate
3. Middle Layer: 35μm Finished Copper
4. Core Dielectric: 3mm F4BM265 PTFE Glass Fiber Composite Core
5. Middle Layer: 35μm Finished Copper
6. Dielectric: S1000-2MB Prepreg + 0.5mm S1000-2M Substrate
7. Layer 4: 35μm Finished Copper

Total Pressed Thickness: 4.14mm

 

4. Production & Quality Standards

Specification Item	Technical Standard & Details
Board Dimension	245mm × 245mm (1PCS)
Layer Count	4-Layer High-Frequency Hybrid Rigid PCB
Finished Copper Weight	35μm per layer
Hole Copper Thickness	25μm (IPC-Class-3 Standard)
Special Process	Blind Via Fabrication + Custom Impedance Control
Surface Finish	ENIG
Solder Mask	Top & Bottom Blue Solder Mask
Silkscreen	Top & Bottom White Legend
Quality Criterion	IPC-Class-3 High-Reliability Standard
Artwork Format	Gerber RS-274-X

5. F4BM Series & F4BM265 CCL Introduction

F4BM, F4BME and F4BM265 are upgraded high-frequency PTFE glass fiber copper clad laminates developed for professional RF and microwave industries. Manufactured with scientifically proportioned PTFE resin, ultra-stable glass fiber cloth and PTFE thin film through high-precision pressing craftsmanship, this series of CCL achieves comprehensive electrical performance upgrades compared with traditional F4B substrates. Featuring wider adjustable dielectric constant range, ultra-low dielectric loss, increased insulation resistance and more stable high-frequency parameters, F4BM series laminates serve as reliable domestic alternatives to imported high-end microwave substrate materials.

The F4BM series laminates feature a differentiated material design for diverse application scenarios. F4BM and F4BME share identical dielectric core composition but adopt different copper foil configurations to match distinct technical indicators. The standard F4BM version is paired with ED copper foil, suitable for conventional RF projects without strict PIM requirements. In contrast, the upgraded F4BME model adopts reversed RTF copper foil, delivering excellent PIM performance, ultra-precise circuit etching control and minimized conductor loss for high-sensitivity microwave systems.

By precisely adjusting the mixing ratio of PTFE resin and glass fiber cloth, F4BM series substrates achieve flexible dielectric constant customization while maintaining low-loss characteristics. Higher glass fiber content enables higher Dk values, better dimensional stability, lower thermal expansion coefficient and superior temperature drift resistance, ensuring reliable parameter consistency under variable working temperatures.

6. Key Technical Features of F4BM265 Substrate

1. Customizable Dielectric Constant: Supports adjustable Dk values from 2.17 to 3.0 with personalized customization available, covering diverse high-frequency design requirements
2. Ultra-Low Microwave Loss: Optimized PTFE and glass fiber composite structure effectively reduces high-frequency signal attenuation for pure and stable microwave transmission
3. Excellent PIM Performance (F4BME): RTF reversed copper foil configuration eliminates signal interference and improves passive intermodulation indicators for high-precision antenna systems
4. Superior Dimensional Stability: Tunable glass fiber proportion lowers thermal expansion and temperature drift, maintaining precise board size in thermal cycling environments
5. Professional Environmental Adaptability: Outstanding radiation resistance and ultra-low outgassing properties, compliant with aerospace and high-end communication environmental standards
6. Cost-Effective Mass Production: Mature industrial production process supports commercial large-batch manufacturing, providing high-cost-performance high-frequency substrate solutions
7. Balanced Performance Design: Realizes perfect trade-off between low dielectric loss and structural stability, solving the performance contradiction of traditional single PTFE materials

7. Typical Application Fields

F4BM265 4-layer hybrid PCBs and F4BM series CCL materials are widely adopted in high-end microwave and RF communication fields, especially suitable for high-precision, low-loss and high-stability circuit scenarios:

1. Microwave & RF wireless communication systems
2. Civil and military radar equipment
3. Phase shifters and passive microwave components
4. Power dividers, couplers and combiners
5. Antenna feed network systems and phased array antenna modules
6. Satellite communication devices and base station antenna hardware

8. Product Overall Summary

F4BM265 4-Layer 4.14mm hybrid ENIG PCB is a high-reliability, impedance-controlled high-frequency circuit board optimized for professional RF and microwave applications. Adopting a composite stackup of 3mm F4BM265 core and S1000-2M series dielectric materials, this 4-layer PCB features uniform 35μm full-layer copper, 25μm IPC-Class-3 standard hole copper, blind via structure and dual-side blue solder mask with white silkscreen. Inheriting F4BM series’ customizable Dk, low-loss, anti-radiation and low-outgassing advantages, it supports high-precision impedance control and mass commercial production. Ideal for radar systems, phased array antennas, satellite communication and passive microwave component manufacturing, F4BM265 hybrid PCB provides stable, cost-effective and high-performance solutions for modern high-frequency communication industries.

 

9.F4BM265 Datasheet

Item	Test Condition	Unit	F4BM265
Typical Dielectric Constant	10GHz	/	2.65
Dielectric Constant Tolerance	/	/	±0.05
Typical Dissipation Factor	10GHz	/	0.0013
Typical Dissipation Factor	20GHz	/	0.0019
Temperature Coefficient of Dielectric Constant	-55℃ ~ 150℃	PPM/℃	-100
Peel Strength (1 OZ F4BM)	1 OZ F4BM	N/mm	＞1.8
Peel Strength (1 OZ F4BME)	1 OZ F4BME	N/mm	＞1.6
Volume Resistivity	Normal Temperature	MΩ·cm	≥6×10⁶
Surface Resistivity	Normal Temperature	MΩ	≥1×10⁶
Dielectric Strength (Z-axis)	5KW, 500V/s	MΩ	＞25
Breakdown Voltage (XY-axis)	5KW, 500V/s	KV	＞34
Coefficient of Thermal Expansion (XY-axis)	-55℃ ~ 288℃	ppm/℃	14~17
Coefficient of Thermal Expansion (Z-axis)	-55℃ ~ 288℃	ppm/℃	142
Thermal Stress	260℃, 10s, 3 cycles	/	No Delamination
Water Absorption	20±2℃, 24h	%	≤0.08
Density	Normal Temperature	g/cm³	2.25
Continuous Operating Temperature	Temperature Chamber	℃	-55 ~ +260
Thermal Conductivity (Z-axis)	/	W/(M·K)	0.36
PIM Value (Only for F4BME)	Only for F4BME	dBc	≤-159
Flame Retardancy	/	UL-94	V-0
Material Composition	/	/	PTFE, Fiberglass ClothF4BM matched with ED copper foil; F4BME matched with reversed RTF copper foil

Tags：F4BM265 and S1000-2M PCB, 4-Layer 4.14mm High Frequency PCB, Hybrid S1000-2M PCB, IPC-Class-3 PCB, Impedance Controlled PCB, ENIG Microwave PCB, PTFE Glass Fiber CCL, Low Loss Radar PCB, Phased Array Antenna PCB, Satellite Communication PCB, F4BME PIM PCB, High Reliability Passive Component PCB