Wangling 2-Layer F4BME220 PCB  3.9 mil DK 2.2 Laminate  Immersion Gold Surface Finish

Document Overview

This article provides a comprehensive technical description of a 2-layer rigid PCB fabricated on Wangling F4BME220, a PTFE-glass-fiber high-frequency laminate with a 0.1 mm (3.9 mil) dielectric core and Immersion Gold surface finish. Part I covers the PCB construction, stackup, design statistics, manufacturing quality, and applications. Part II presents a detailed CCL technical reference including a complete data sheet, available configurations, and material characteristics.

Part I: 2-Layer F4BME220 PCB

1. Product Overview

The 2-layer F4BME220 PCB is an ultra-thin, high-frequency rigid circuit board for microwave and RF applications where low loss and compact form factor are critical. Built on a 0.1 mm (3.9 mil) F4BME220 core — a PTFE laminate reinforced with glass fiber cloth and clad with RTF copper — this board delivers Dk 2.2 at 10 GHz (±0.04) and Df 0.001 at 10 GHz (0.0014 at 20 GHz). Finished thickness is just 0.1 mm, with 1 oz (35 μm) copper on both layers and Immersion Gold finish.

Dk 2.2 places F4BME220 at the low end of PTFE laminates, ideal for wide-bandwidth, low-dispersion lines. Unlike FR-4, it maintains stable Dk and low loss at microwave frequencies. Its 0.1 mm thickness — among the thinnest rigid RF substrates — enables compact assemblies for phased-array antennas, satellite modules, and portable microwave equipment. RTF copper reduces conductor loss and delivers PIM ≤ −159 dBc, a key differentiator for high-linearity RF front-ends.

2. Key Performance Highlights

· Dk 2.2 ± 0.04 at 10 GHz — among the lowest in glass-fiber-reinforced PTFE laminates.

· Df 0.001 at 10 GHz, 0.0014 at 20 GHz — ultra-low insertion loss.

· PIM ≤ −159 dBc (RTF copper) — minimal intermodulation distortion.

· Ultra-thin 0.1 mm finished thickness (3.9 mil core).

· Operating range −55 °C to +260 °C; UL-94 V-0; moisture absorption ≤ 0.08 %.

· Immersion Gold finish — flat, coplanar, oxidation-resistant.

3. PCB Construction Details

The table below summarizes the physical dimensions, fabrication parameters, and quality specifications.

4. PCB Stackup

The board uses a symmetric 2-layer stackup with equal 1 oz copper on both sides of the F4BME220 core.

5. PCB Statistics

The design statistics below provide a quantitative snapshot of the circuit's complexity.

6. Manufacturing & Quality Assurance

This Wangling PCB uses established PTFE laminate processing. F4BME220's dimensional stability (CTE 25–34 ppm/°C X/Y) ensures registration accuracy, demonstrated by 5/8 mil trace/space and 0.25 mm minimum hole. The 0.1 mm core requires careful handling during lamination and drilling.

All boards are 100 % electrically tested and produced to IPC-Class-2 with Gerber RS-274-X artwork. Immersion Gold provides a flat, coplanar surface for fine-pitch SMT and RF connectors, with superior shelf life over HASL. The single-sided green solder mask and white top silkscreen leave the bottom bare to minimize dielectric discontinuities in RF-critical areas.

7. Typical Applications

· Phased-array antenna elements and feed networks.

· Satellite communication payloads and ground terminals (Ku/Ka bands).

· Power dividers, couplers, and combiners.

· Phase shifters, passive components, and base station antennas.

· Portable and airborne microwave equipment.

8. PCB Conclusion

The 2-layer F4BME220 Immersion Gold PCB with a 0.1 mm core is a purpose-built solution for high-frequency applications demanding ultra-low Dk, minimal insertion loss, and compact form factor. Its PTFE-glass-fiber substrate delivers Dk 2.2 ±0.04 and Df as low as 0.001 at 10 GHz, while RTF copper provides PIM ≤ −159 dBc. With IPC-Class-2 quality, 100 % electrical testing, and a −55 °C to +260 °C rating, this board is well positioned for phased-array antennas, satellite communications, and microwave RF systems where low Dk, low loss, and thin profile are essential.

Part II: F4BME220 Copper-Clad Laminate (CCL) — Technical Reference

1. Introduction to the F4BME / F4BM Series

F4BME series laminates are manufactured by pressing fiberglass cloth, PTFE resin, and PTFE film. Compared to the earlier F4B generation, F4BME offers a wider Dk range, lower loss, higher insulation resistance, and enhanced stability — a viable substitute for imported high-frequency laminates.

F4BM and F4BME share the same dielectric but differ in copper: F4BM uses ED copper for non-PIM applications, while F4BME uses RTF copper for PIM ≤ −159 dBc, precise line control, and lower conductor loss. Dk is tuned by the PTFE-to-glass ratio: higher Dk grades contain more glass for better stability at modestly higher loss. F4BME220 (Dk 2.2) is optimized for minimum loss and maximum bandwidth.

2. Key Features of F4BME220

· Dk 2.17–3.0 across the series; customizable for specific applications.

· Ultra-low Df (0.001 at 10 GHz).

· RTF copper with PIM ≤ −159 dBc.

· Diversified panel sizes and thicknesses.

· Radiation resistance and low outgassing for aerospace.

· Minimum dielectric thickness 0.1 mm.

3. Complete Data Sheet

The table below presents complete electrical, mechanical, thermal, and physical property data for F4BME220. All values are typical measurements per IPC-TM-650 or GB/T 4722-2017.

Notes: (1) Dk measured in Z direction by stripline method per GB/T 12636-1990 or IPC-TM-650 2.5.5.5. (2) Other properties per IPC-TM-650 or GB/T 4722-2017. (3) All values are typical measurements for material selection and do not constitute a warranty; customers must verify suitability for each application.

4. Available Copper Foil Options

· F4BME (RTF): 0.5 oz (0.018 mm), 1 oz (0.035 mm) — low conductor loss, excellent PIM.

· F4BM (ED): 0.5 oz, 1 oz, 1.5 oz (0.05 mm), 2 oz (0.07 mm) — for non-PIM applications.

· Aluminum base (F4BME220-AL): shielding and thermal dissipation.

· Copper base (F4BME220-CU): maximum thermal conductivity for high-power RF.

5. Available Panel Sizes

• Standard panels: 460 × 610, 500 × 600, 850 × 1200, 914 × 1220, and 1000 × 1200 mm. 
• Custom sizes (300 × 250, 350 × 380, 500 × 500, 840 × 840, 1000 × 1500 mm) available on request. For thicknesses ≥ 4.0 mm or ≤ 0.2 mm, maximum panel size is 500 × 610 mm.

6. Available Dielectric Thicknesses

F4BME220 substrate minimum dielectric thickness is 0.1 mm. Standard thicknesses and tolerances are listed below. Customers should specify whether thickness includes copper (total) or dielectric only.

7. Aluminum / Copper Base Laminates

F4BME can be supplied with a metal base (aluminum or copper) on one side and copper foil on the other, providing electromagnetic shielding and enhanced thermal dissipation. Models: F4BME220-AL (aluminum base) and F4BME220-CU (copper base).

8. F4BME220 Laminate Product Image

The image below shows the F4BME220 copper-clad laminate material.

Figure 1: F4BME220 Copper-Clad Laminate

9. CCL Conclusion

F4BME220 is a low-Dk (2.2), ultra-low-loss PTFE-glass-fiber laminate combining competitive electrical performance with practical manufacturability. Its Df of 0.001 at 10 GHz, PIM ≤ −159 dBc (RTF copper), and minimum dielectric thickness of 0.1 mm suit phased-array antennas, satellite communications, and wide-bandwidth microwave circuits. With thicknesses from 0.1 mm to 12 mm, multiple panel sizes, RTF/ED copper options, and aluminum/copper metal-backed variants, F4BME220 offers a flexible, cost-effective alternative to imported high-frequency laminates. Its UL-94 V-0 rating, −55 °C to +260 °C range, and low moisture absorption further support use in demanding industrial, aerospace, and telecommunications environments.