Wangling 2-Layer F4BM255 3.0mm DK2.55 Substrate 2oz Heavy Copper ENIG PCB

Wangling 2-Layer F4BM255 3.0mm DK2.55 Substrate 2oz Heavy Copper ENIG PCB

Part 1: PCB Product Core Introduction

1.1 Product Overview

This custom two-layer rigid RF/microwave printed circuit board is built on Taizhou Wangling Insulation Factory’s F4BM255 PTFE glass fabric copper-clad laminate (CCL), with a full dielectric core thickness of 3.0mm, targeted for medium-to-high frequency RF circuits without strict Passive Intermodulation (PIM) requirements. The finished board dimension is 521mm×59mm (1 piece only), adopting 2oz heavy copper outer layers, immersion gold surface finish, single-sided green solder mask and single-sided white silkscreen.

F4BM255 substrate is engineered to balance low high-frequency dielectric loss and dimensional stability, outperforming traditional F4B series PTFE laminates with tighter DK tolerance, elevated insulation resistance and consistent electrical performance across -55°C to +260°C operating temperature range. This 2-layer Wangling PCB design eliminates blind/buried vias and relies purely on through-hole interconnection, simplifying fabrication while preserving critical signal integrity for microwave passive components, short-range radar feed networks and medium-power RF antenna assemblies. The 2oz thick copper construction reduces conductor loss under continuous RF power loading, while immersion gold surface finish delivers excellent oxidation resistance, stable contact impedance for SMT component soldering and long-term storage durability without black pad defects.

1.2 PCB Construction Details

Full mechanical, material and surface finishing specifications of the2-layer F4BM255 PCB

1.3 PCB Stackup Structure

This two-layer stackup adopts symmetrical single-core PTFE structure without prepreg interlayers, featuring uniform heavy copper cladding on both sides of thick F4BM dielectric core.

1.4 PCB Circuit Statistical Data

Quantitative circuit metrics including pads, vias, nets and component count for design reference

1.5 Manufacturing & Application Differentiation Advantages

1) Low-loss high-frequency substrate advantage: F4BM255 delivers DF = 0.0013 @10GHz, drastically reducing signal attenuation for microwave frequency bands from 2GHz to 20GHz;2)tighter DK tolerance±0.05 ensures consistent impedance matching across full panel length of 521mm.

3) 2oz heavy copper performance: Thick copper layer minimizes skin-effect conductor loss under continuous RF power, suitable for power divider, coupler and medium-power antenna feed circuits where high current throughput is required.

4) Controlled thermal mechanical stability: F4BM255 XY-axis CTE only 16–21 ppm/°C, preventing trace cracking during reflow (260°C peak temperature) and long-term cyclic temperature variation from -55°C to 260°C.

5) Cost-optimized single-sided coating scheme: Eliminating bottom solder mask and silkscreen cuts raw material and coating labor cost while retaining full trace protection on the signal-carrying top surface.

6) Large-format customized capability: Supports non-standard long strip dimension 521mm×59mm, compatible with linear antenna arrays, series-connected passive RF module assemblies that require extended PCB length.

1.6 PCB Conclusion

This 2-layer F4BM255 3.0mm laminate PCB is a cost-effective, high-performance microwave circuit solution balancing low dielectric loss, dimensional stability and heavy-current transmission capacity. Its standardized fabrication rules (IPC-Class-2), worldwide production compatibility via Gerber RS-274-X artwork, and flexible customized dimension capability make it a mature substitute for imported foreign PTFE RF PCBs for non-PIM sensitive RF passive and antenna systems. The simplified through-hole-only stackup reduces manufacturing difficulty and lead time, while the single-sided green mask + white silkscreen layout achieves optimal balance between functional protection and project cost control, covering mainstream commercial microwave communication application scenarios.

Part 2: Supporting CCL Deep Technical Explanation–F4BM255 PTFE Glass Fabric Copper Clad Laminate

2.1 CCL Product Definition & Raw Material Formulation

F4BM255 is a PTFE woven glass fabric reinforced copper-clad laminate manufactured by Taizhou Wangling Insulation Material Factory, compounded by high-purity polytetrafluoroethylene resin, PTFE film and E-glass woven cloth under precise temperature & pressure lamination molding process. Compared to the base F4B series PTFE substrates, F4BM series upgrades formula uniformity to expand DK adjustable range, lower dissipation factor and raise volume/surface insulation resistance with superior batch-to-batch consistency.

Core classification difference between F4BM and F4BME: identical PTFE-glass dielectric core, differentiated only by attached copper foil type. F4BM series uses standard ED (electrodeposited) copper foil without optimized reverse roughness structure, making it ideal for applications without mandatory PIM performance indicators; F4BME adopts reverse-treated RTF copper foil for ultra-low PIM≤-159 dBc, targeting carrier-grade base station antennas. F4BM255’s 2.55 DK value is tuned by adjusting glass fiber proportion inside PTFE matrix: higher glass loading improves XY dimensional stability, lowers thermal expansion coefficient and temperature drift, with minor trade-off of slightly elevated dielectric loss versus lower-DK pure PTFE substrates.

2.2 Full F4BM255 Datasheet Technical Parameter Table

(Summary: Complete electrical, thermal, mechanical and environmental performance metrics under standardized test conditions)

2.3 Optional Copper Foil, Dimension & Thickness Customization Specifications

2.3.1 Copper Foil Options for F4BM Series

• F4BM base material is pre-cladded with ED electrodeposited copper foil, available thickness grades:

• 0.5OZ (0.018mm), 1OZ (0.035mm), 1.5OZ (0.05mm), 2OZ (0.07mm)

This PCB project selects 2oz ED copper matching the high-current circuit design requirement.

2.3.2 Standard & Customizable Panel Sizes

• Standard factory stock dimensions: 460×610mm, 500×600mm, 850×1200mm, 914×1220mm, 1000×1200mm

• Custom non-standard sizes available upon request: 300×250mm, 350×380mm, 500×500mm, 840×840mm, 1000×1500mm

• Size restriction rule: dielectric thickness≤0.2mm or≥4.0mm, maximum panel dimension limited to 500×610mm. The target PCB’s 521mm length falls within allowable cutting range for 3.0mm thick F4BM255 core.

2.3.3 Standard Dielectric Thickness & Tolerance Chart

Available core dielectric thickness covers 0.1mm minimum (DK≤2.65) up to 12.0mm thick substrate, with graded dimensional tolerances based on thickness:

• Thin core: 0.1mm / 0.127mm, tolerance±0.01mm
• Medium core: 0.2~0.762mm, tolerance±0.02~±0.05mm
• Thick core (target grade 3.0mm): tolerance±0.09mm

 Ultra-thin (<0.1mm) or extra-thick (>12mm) dielectric layers support customized development via factory special pressing process.

2.4 Optional Derivative Products: F4BM255 Metal-Base Substrates

F4BM255 can be laminated with aluminum base or copper base to form heat-dissipating shielded metal-clad CCL, model naming rule:

• F4BM255-AL: F4BM255 dielectric bonded to aluminum alloy base
• F4BM255-CU: F4BM255 dielectric bonded to pure brass/copper base

Metal base thickness options: 0.48mm, 0.98mm, 1.48mm, 1.98mm, 2.98mm, 3.98mm, tolerance +0.02/-0.05mm. Metal-base laminates are used for high-power RF modules requiring passive heat sinking and electromagnetic shielding integration.

2.5 Core Product Characteristics of F4BM255 CCL

1)Wide adjustable DK spectrum (2.17~3.0 customizable), fixed nominal DK 2.55 for this series grade with tight±0.05 tolerance for stable impedance control.

2)Ultra-low high-frequency dielectric loss, maintaining DF below 0.002 across 10–20GHz frequency band, critical for long-distance signal transmission in antenna feed networks.

3)Glass-reinforced matrix delivers excellent dimensional stability and low XY CTE, preventing PCB warpage and trace fracture under wide temperature fluctuation.

4)Multi-size panel & multi-thickness dielectric customization capability, reduces material waste for long-strip PCB designs like the 521mm-length product.

5)Radiation-resistant and low outgassing performance, compliant with aerospace and satellite communication component material requirements.

6)Mass industrialized production with cost competitiveness, serves as domestic replacement solution for imported foreign PTFE microwave laminates.

2.6 Typical Industrial Application Fields for F4BM255 CCL

All circuits fabricated on F4BM255 substrate fit RF/microwave systems without strict PIM testing standards:

• L-band / S-band microwave radar transceiver boards
• Passive RF components: phase shifters, power dividers, directional couplers, signal combiners
• Phased array antenna feed network backplanes
• Satellite communication ground terminal RF modules
• Macro & micro base station antenna control circuits
• General RF test fixture and signal matching boards

2.7 CCL Material Conclusion

F4BM255 PTFE glass fabric copper-clad laminate is a balanced-performance high-frequency substrate optimized for cost-sensitive commercial microwave electronics. Its precisely controlled 2.55 dielectric constant, ultra-low dissipation factor, reinforced glass matrix thermal stability and full customization of thickness, panel size and copper foil weight make it the ideal base material for the 2-layer 3.0mm thick RF PCB described above. Distinguished from low-PIM F4BME variant by standard ED copper foil configuration, F4BM255 eliminates unnecessary reverse copper surface processing cost while retaining core low-loss dielectric performance, positioning it as the preferred substrate for non-PIM critical RF antenna, radar and passive component manufacturing with stable domestic supply chain and import substitution value.