F4BTD350S High-Thermal-Conductivity PTFE Laminate Q&A: Dk 3.5, Df 0.0016, 1.25 W/m·K – Is It Right for Your High-Power RF PCB?

Product Description

What is F4BTD350S?

It is a high-thermal-conductivity PTFE resin high-frequency substrate. It is reinforced with glass fiber cloth. It contains a large amount of high-thermal-conductivity special ceramics. The dielectric constant (Dk) is 3.5 ±0.07 at 10 GHz. The dissipation factor (Df) is 0.0016 at 10 GHz. The thermal conductivity is 1.25 W/(m·K). This is significantly higher than standard PTFE materials. The material has a CTE of 11/10 ppm/°C in the X/Y axes and 40 ppm/°C in the Z axis. The decomposition temperature (Td) is 500°C. The material is UL94 V-0 rated. It has very low moisture absorption (0.05%). It is ideal for high-power RF applications that require low insertion loss and efficient heat dissipation.

 

 

What PCB can be built with it?

A complete 2-layer RF PCB solution can be provided. The board is based on F4BTD350S material. The finished thickness is 0.6 mm. The copper weight is 1 oz per layer. Immersion gold is applied as the surface finish. Black solder mask is applied on the top layer. White silkscreen is printed on the top layer. No solder mask or silkscreen is applied on the bottom layer. The minimum trace and space are 7 and 9 mils. The minimum hole size is 0.6 mm. Via plating thickness is 20 µm. The quality standard is IPC Class 2. This board is ideal for high-power RF amplifiers, antennas, couplers, filters, and industrial heating equipment.

 

 

1. Material Overview

The F4BTD350S is a high-thermal-conductivity PTFE resin high-frequency substrate. It is manufactured by Taizhou Wangling Insulating Materials Factory. It is reinforced with glass fiber cloth. It contains a large amount of high-thermal-conductivity special ceramics.

 

This material is a new generation of high-frequency materials. It was developed for applications that require low insertion loss and high heat dissipation efficiency. It can replace similar foreign products.

 

The excellent low loss and thermal conductivity performance increase the microwave power tolerance. The service life of devices is extended. The material is more suitable for high-temperature and long-term operation. Equipment reliability is ensured. Low-cost maintenance is achieved.

 

The material also has the following advantages:

 

Low thermal expansion coefficient

 

Dimensional stability

 

High electrical strength

 

High insulation performance

 

These advantages make PCB processing easier. Through-hole reliability is higher. Soldering faults are lower. Component matching is better. Environmental adaptability is stronger.

 

The circuit boards can be processed using standard PTFE sheet technology. The excellent mechanical and physical properties make the material suitable for multilayer, high-multilayer, and backplane processing. It also shows excellent processability in dense hole and fine-line processing.

 

 

 

2. F4BTD350S Technical Data Sheet

Property	Test Condition	Unit	F4BTD350S Value
Dielectric Constant (Typical)	2 GHz	—	3.52
	10 GHz	—	3.5
DK Tolerance	—	—	±0.07
Dielectric Constant (Design)	10 GHz	—	3.62
Loss Factor (Typical)	2 GHz	—	0.0012
	10 GHz	—	0.0016
TCDk	-55°C to 150°C	ppm/°C	-45
Peel Strength (1 oz copper foil)	—	N/mm	>0.8
Volume Resistivity	C96/23/95	MΩ·cm	1×10¹¹
Surface Resistance	C96/23/95	MΩ	1×10¹²
Electric Strength (Z-direction)	5 kW, 500 V/s	kV/mm	25
Breakdown Voltage (Horizontal)	5 kW, 500 V/s	kV	38
Relative Tracking Index (CTI)	23°C/50%/24H	V	600
CTE (X-axis)	-55°C to 288°C	ppm/°C	11
CTE (Y-axis)	-55°C to 288°C	ppm/°C	10
CTE (Z-axis)	-55°C to 288°C	ppm/°C	40
Thermal Decomposition Temp (Td)	5% mass loss	°C	500
Flexural Strength (X/Y)	Normal state	MPa	74/64
Tensile Strength (X/Y)	Normal state	MPa	48/45
Flexural Modulus (X/Y)	Normal state	MPa	7500/7000
Dimensional Stability (X/Y)	After etching and baking	%	0.08/0.18
Thermal Stress	260°C/10s/3 times	—	No delamination
Thermal Conductivity	Z-direction	W/(m·K)	1.25
Specific Heat Capacity	—	J/g·°C	0.8
Density	Normal temperature	g/cm³	2.21
Long-term Service Temperature	—	°C	-55 to +260
Water Absorption	20±2°C, 24 hours	%	0.05
Flame Retardancy	UL94	Rating	V-0
Dielectric Layer Composition	—	—	PTFE + Glass Fiber Cloth + High-Thermal-Conductivity Ceramics

 

 

3. Application Fields

- High power radio frequency

- Power amplifier

- Antenna

- Industrial heating equipment

- Couplers, filters, power splitters

 

 

4. Custom 2-Layer RF PCB – Complete Specification

A complete 2-layer RF PCB solution can be provided based on F4BTD350S. 

 

 

Board Specifications

Specification	Detail
Board Type	2-Layer RF PCB
Base Material	F4BTD350S (0.508 mm / 20 mil core)
Finished Board Thickness	0.6 mm
Finished Copper Weight	1 oz (35 µm) per layer
Board Dimensions	79 × 110 mm (1 piece)
Dimension Tolerance	±0.15 mm
Minimum Trace / Space	7 / 9 mils
Minimum Hole Size	0.6 mm
Via Plating Thickness	20 µm
Surface Finish	Immersion Gold (ENIG)
Top Solder Mask	Black
Bottom Solder Mask	No
Top Silkscreen	White
Bottom Silkscreen	No
IPC Classification	Class 2
Artwork Format	Gerber RS-274-X
Testing	100% Electrical Test (before shipment)
Availability	Worldwide

 

 

5. Key Benefits of This PCB Design

Feature	Benefit
2-layer RF design is used	Simple and cost-effective RF circuit implementation is achieved
F4BTD350S core (0.508 mm) is used	High thermal conductivity (1.25 W/m·K) dissipates heat efficiently; low loss (0.0016) ensures signal integrity
7/9 mil trace and space are used	Fine-line, high-density RF circuits can be produced
Black solder mask is applied on top	Professional appearance; top-layer circuits are protected
No solder mask on bottom	Thermal dissipation is improved; grounding strategies are enabled
Immersion gold finish is applied	Excellent solderability; oxidation resistance; flat surface
20 µm via plating is used	Reliable plated through-hole connections are ensured
IPC Class 2 quality is met	Commercial and industrial quality standards are satisfied
100% electrical test is performed	Functional integrity is guaranteed before shipment

 

 

Q1: What is the dielectric constant of F4BTD350S?

The typical Dk is 3.5 ±0.07 at 10 GHz. The design Dk is 3.62 at 10 GHz. The Dk is stable over temperature with a TCDk of -45 ppm/°C.

 

 

Q2: What is the thermal conductivity of F4BTD350S?

The thermal conductivity is 1.25 W/(m·K) in the Z-direction. This is significantly higher than standard PTFE materials. It allows efficient heat dissipation in high-power RF applications.

 

 

Q3: Is F4BTD350S suitable for high-power RF applications?

Yes. The material was specifically developed for high-power RF applications. The high thermal conductivity (1.25 W/(m·K)) dissipates heat efficiently. The low loss (0.0016) minimizes signal attenuation. The high power tolerance allows high microwave power levels to be handled.

 

 

Q4: What thicknesses are available for F4BTD350S?

Dielectric thicknesses are available from 0.127 mm (5 mil) to 6.35 mm (250 mil). Standard sizes include 305×460 mm and 460×610 mm. Copper foil thicknesses of 0.5 oz and 1 oz are standard. Other thicknesses can be customized.

 

 

Q5: Where can the official F4BTD350S data sheet be obtained?

The official data sheet is available from Taizhou Wangling Insulating Materials Factory. Please contact our team. We can provide the documentation. We can also direct you to the manufacturer's technical support.

 

 

Ready to Get Started?

F4BTD350S raw laminate can be provided. Metal-backed variants (aluminum or copper) are also available. Fully fabricated 2-layer RF PCBs with immersion gold finish can be manufactured.

 

Contact us today for:

 

Material sampling and testing

 

RF circuit design assistance

 

Impedance calculation and design support

 

PCB quoting and DFM review

 

Technical support for your specific application