Wangling F4BTM300 Custom 2-layer PCB 20mil DK3.0 Substrate with Immersion Gold

High-Frequency RF Printed Circuit Board — Technical Product Description

Part I: PCB Product Description

Executive Summary

This  description presents a comprehensive technical overview of the Wangling F4BTM300 PCB, a 2-layer rigid high-frequency printed circuit board built on a 20mil (0.508 mm) F4BTM300 PTFE ceramic-filled core with an immersion gold surface finish. Engineered for microwave and RF applications requiring stable dielectric performance at gigahertz frequencies, this Wangling DK3.0 board combines a dielectric constant (Dk) of 3.0 ±0.06 at 10 GHz with an ultra-low dissipation factor (Df) of 0.0018.

The following sections detail the PCB construction, layer stackup, manufacturing statistics, key electrical and thermal performance metrics, and target applications. A dedicated CCL (copper-clad laminate) material datasheet section follows, providing complete substrate specifications, copper foil options, dimensional availability, and metal-backed variants.

1. Product Overview

The Wangling F4BTM300 PCB is a 2-layer rigid high-frequency circuit board designed for applications demanding precise impedance control and minimal signal loss at microwave frequencies. At its core lies a 0.508 mm (20 mil) F4BTM300 dielectric — a polytetrafluoroethylene (PTFE) resin system reinforced with glass fiber cloth and loaded with nano-ceramic fillers. This material architecture delivers a stable dielectric constant of 3.0 ±0.06 at 10 GHz and a dissipation factor as low as 0.0018, making it well-suited for RF feed networks, phased array antennas, radar systems, and satellite communications equipment.

2. PCB Construction Details

The table below summarizes the complete construction specifications of the F4BTM300 PCB, covering base material, geometry, copper weighting, via plating, surface finish, and quality assurance parameters.

3. PCB Stackup

The board employs a symmetric 2-layer stackup with 35 μm copper foil on both sides of a0.508 mm F4BTM300 core, yielding a finished board thickness of approximately 0.6 mm.

4. PCB Statistics

This board accommodates 13 components across 94 total pads — comprising 51 through-hole pads and 43 top-side SMT pads — with 36 vias and 2 electrical nets, reflecting a compact, high-density RF layout.

5. Key Performance Characteristics

The F4BTM300 substrate's electrical and thermal properties define the board's high-frequency performance. The dielectric constant of 3.0 ±0.06 at 10 GHz is tightly controlled, and its thermal coefficient of -75 ppm/°C (measured from -55°C to 150°C) ensures that characteristic impedance remains stable across wide temperature swings — a critical requirement for aerospace and outdoor radar systems. The dissipation factor of 0.0018 at 10 GHz (rising only marginally to 0.0023 at 20 GHz) minimizes insertion loss in transmission lines and feed networks.

Thermally, the material exhibits a coefficient of thermal expansion (CTE) of 15 ppm/°C in the X-axis and 16 ppm/°C in the Y-axis, closely matching copper's CTE (~17 ppm/°C) and reducing thermally induced stress on plated through-holes and solder joints during temperature cycling. The Z-axis CTE of 72 ppm/°C (measured -55°C to 288°C) is notably low for a PTFE-based system, attributable to the nano-ceramic filler loading. The substrate supports a long-term operating temperature range of -55°C to +260°C and withstands thermal stress at 260°C for 10 seconds across 3 cycles without delamination.

Additional material properties include a volume resistivity of ≥1×10⁷ MΩ·cm, surface resistance of ≥1×10⁶ MΩ, electrical strength exceeding 30 kV/mm in the Z-direction, and breakdown voltage above 35 kV in the XY-plane. Moisture absorption is ≤0.05% after 24 hours at 20±2°C, and the material achieves a UL-94 V-0 flammability rating. Thermal conductivity is 0.42 W/(m·K) in the Z-direction, and density is 2.25 g/cm³. Peel strength exceeds 1.6 N/mm for 1 oz F4BTM copper foil, ensuring robust copper-to-dielectric adhesion.

The immersion gold surface finish provides a contact resistance suitable for high-frequency signal interfaces and ensures consistent solderability during assembly. The 20 μm via plating thickness meets IPC-Class-2 requirements for hole-wall integrity and reliability. The minimum trace/space of 5/8 mils and minimum hole size of 0.35 mm demonstrate the board's capability for fine-feature high-frequency routing.

6. Typical Applications

The 2-layer F4BTM300 ENIG PCB is targeted at the following application domains:

· Aerospace equipment, space and cabin electronics

· Microwave and RF circuits

· Radar systems, including military radar

· Feed networks for antenna arrays

· Phase-sensitive antennas and phased array antennas

· Satellite communications systems

7. PCB Conclusion

The F4BTM300 PCB 20mil Immersion Gold represents a purpose-built high-frequency circuit solution that leverages the stable dielectric and low-loss characteristics of PTFE ceramic-filled laminate. With its tightly controlled Dk of 3.0 ±0.06, ultra-low Df of 0.0018 at 10 GHz, CTE closely matched to copper, and a broad operating temperature range from -55°C to +260°C, this board addresses the stringent requirements of aerospace, radar, and satellite communication systems.

The immersion gold finish, 100% electrical testing, and IPC-Class-2 compliance further ensure reliability and assembly readiness. For engineers evaluating substrate options, the following CCL datasheet section provides completeF4BTM300 laminate specifications to support material selection and design trade-off analysis.

Part II: F4BTM300 CCL (Copper-Clad Laminate) Material Datasheet

1. Material Introduction

The F4BTM300 is a member of the F4BTM series ofPTFE-based high-frequency laminates manufactured by Taizhou Wangling Insulation Materials Factory. The series is produced through a scientifically formulated process combining glass fiber cloth, nano-ceramic fillers, and polytetrafluoroethylene (PTFE) resin, pressed under strict process controls.

Built upon the F4BM dielectric platform, the F4BTM series incorporates high-dielectric-constant, low-loss nano-scale ceramics into the PTFE matrix. This integration yields an elevated dielectric constant, improved heat resistance, a reduced coefficient of thermal expansion, higher insulation resistance, and enhanced thermal conductivity — all while preserving the inherently low-loss characteristics of PTFE.

The F4BTM variant is paired with standard ED (electrodeposited) copper foil and is intended for applications without PIM (passive intermodulation) requirements. The F4BTME variant uses reverse-treated RTF (reverse treatment foil) copper foil, delivering exceptional PIM performance (≤-160 dBc), more precise line-width control, and lower conductor loss. Both variants share the same dielectric layer composition; the distinction lies solely in the copper foil treatment.

2. Product Features

· Dielectric constant Dk range of 2.98–3.5 available across the series; F4BTM300 specified at Dk 3.0

· Nano-ceramic filler loading enhances dielectric, thermal, and mechanical performance versus unfilled PTFE

· F4BTME variant offers excellent PIM characteristics (≤-160 dBc) with reverse-treated RTF copper foil

· Wide range of available thicknesses (0.254 mm to 12.0 mm) and panel sizes for cost optimization

· Commercialized, high-volume production with competitive pricing

· Radiation-resistant and low-outgassing properties suitable for space and high-altitude applications

· UL-94 V-0 flammability rating for safety-critical deployments

3. Complete Technical Datasheet

The following table provides the complete electrical, thermal, mechanical, and environmental specifications for the F4BTM300 laminate, as measured per IPC-TM-650 and GB/T standard test methods.

4. Copper Foil Options

The F4BTM300 laminate is available with two copper foil configurations, determined by the application's PIM and conductor-loss requirements:

· F4BTM (ED copper foil): 0.5 oz (0.018 mm), 1 oz (0.035 mm), 1.5 oz (0.05 mm), 2 oz (0.07 mm)

· F4BTME (Reverse RTF copper foil): 0.5 oz (0.018 mm), 1 oz (0.035 mm)

The choice between ED and RTF copper foil depends on the application's PIM requirements and conductor loss budget. RTF foil's smoother matte surface reduces skin-effect losses at microwave frequencies and yields superior PIM performance (≤-160 dBc), making it the preferred choice for high-linearity RF systems such as phased array antennas and sensitive receiver front-ends. ED foil is suitable for cost-sensitive applications where PIM performance is not a design constraint.

5. Available Panel Sizes

Standard panel sizes for the F4BTM300 laminate include:

· 460 × 610 mm

· 600 × 500 mm

· 914 × 1220 mm

Note: For laminate thickness ≥4.0 mm, the 914 × 1220 mm panel size is not available. Customers should confirm panel size availability when ordering thicker gauges.

6. Available Thicknesses and Tolerances

The F4BTM300 is offered in a comprehensive range of standard thicknesses, specified either as total copper-clad thickness or dielectric thickness (customers must specify at time of order). Non-standard thicknesses are available upon request. The table below lists standard thicknesses and corresponding tolerances.

7. Metal-Backed Variants (Aluminum / Copper Base)

The F4BTM and F4BTME series are also available with metal backing — either aluminum or copper — bonded to one side of the dielectric (with copper foil on the opposite side). These variants provide electromagnetic shielding and enhanced thermal dissipation. Designations include F4BTM-AL, F4BTME-AL, F4BTM-CU, and F4BTME-CU.

Example model naming: F4BTM300-AL denotes an F4BTM300 laminate with aluminum backing; F4BTME350-CU denotes an F4BTME350 laminate with copper backing. Other metal base thicknesses are available upon request.

8. F4BTM300 CCL Product Image

Figure 1: F4BTM300 Copper-Clad Laminate

9. Testing Standards and Notes

· Dielectric constant (typical value) is measured in the material Z-direction using GB/T 12636-1990 or IPC-TM-650 2.5.5.5 stripline method.

· Other performance tests follow or reference IPC-TM-650 or GB/T 4722-2017 test methods.

All test data are typical measurements intended to assist customers in material selection. They do not constitute an express or implied warranty, nor do they guarantee that customers will achieve all listed performance in specific applications. Customers are responsible for verifying the suitability of Wangling materials in each application.

10. CCL Conclusion

The F4BTM300 copper-clad laminate is a versatile, commercially mature PTFE-ceramic high-frequency substrate that balances stable dielectric performance (Dk 3.0 ±0.06), ultra-low loss (Df 0.0018 at 10 GHz), and robust thermal-mechanical reliability (CTE matched to copper, -55°C to +260°C operating range, UL-94 V-0). With its broad thickness range from 0.254 mm to 12.0 mm, multiple panel sizes, ED and RTF copper foil options, and aluminum/copper-backed variants, the F4BTM300 offers designers significant flexibility in optimizing cost and performance for aerospace, radar, phased array, and satellite communication applications. 

Its radiation-resistant and low-outgassing characteristics further extend its suitability into space-grade electronics. When paired with the immersion gold PCB fabrication process described in Part I, the F4BTM300 laminate forms a complete, high-reliability solution for demanding microwave and RF systems.