F4B PCB Material Guide — F4BM220 to F4BTM615 Dk/Df Data and Thickness Options
F4B is a PTFE-based RF laminate family produced by Wangling (泰兴旺灵), spanning low-Dk low-loss grades (F4BM220) through mid-Dk general RF grades (F4BM300, F4B350) to high-Dk miniaturization grades (F4BTM440, F4BTM615). This guide covers the Dk/Df properties, standard thickness options, and application guidance for the F4B grade family.
Table of Contents
F4B Material Properties
| Grade | Dk | Df | Standard Thickness Range | Typical Application |
|---|---|---|---|---|
| F4BM220 | 2.20 ±0.04 | 0.0010 | 0.127–3.0mm | Lowest loss F4B grade — wideband, EW, antenna feed |
| F4BM255 | 2.55 ±0.05 | 0.0013 | 0.127–3.0mm | General broadband RF below 18GHz |
| F4BM265 | 2.65 ±0.05 | 0.0015 | 0.127–3.0mm | Similar range to F4BM255, slightly higher Dk |
| F4BM300 | 3.0 ±0.05 | 0.0017 | 0.127–3.0mm | X/Ku-band filters, comparable Dk tier to RO3003 |
| F4B350 | 3.5 ±0.05 | 0.0025 | 0.127–3.0mm | Mid-Dk filter and coupler design |
| F4BTM400 | 4.00 ±0.08 | 0.0030 | 0.127–3.0mm | Higher-Dk designs, size-constrained layouts |
| F4BTM440 | 4.40 ±0.10 | 0.0033 | 0.127–3.0mm | Compact patch antenna, phase shifter |
| F4BTM615 | 6.15 ±0.12 | 0.0045 | 0.127–3.0mm | High-Dk miniaturization, similar tier to RF-60A |
The F4BM series (220/255/265/300) covers the low-to-mid Dk range most commonly specified for general RF and microwave applications. F4BM220 (Dk 2.20, Df 0.0010) is the lowest-loss grade in the range, positioned in a similar performance tier to Rogers RT5880 and Taconic TLY-5. The F4BTM series (400/440/615) covers higher Dk values used for size-constrained designs where physical miniaturization is the primary driver.
Which F4B Grade for Which Application
| Application | F4B Grade | Reason |
|---|---|---|
| Wideband EW / ESM receiver | F4BM220 | Lowest Df in the F4B range — Df 0.0010 |
| General RF below 12GHz | F4BM255 / F4BM265 | Balanced loss and cost for broadband designs |
| X/Ku-band filter or coupler | F4BM300 | Dk 3.0 — comparable tier to Rogers RO3003 for trace geometry |
| Mid-Dk antenna or phase shifter | F4B350 | Dk 3.5 — similar tier to Taconic RF-35 |
| Miniaturized patch element | F4BTM440 / F4BTM615 | High Dk reduces physical element size for compact designs |
F4BM220 — lowest loss in the range
F4BM220 (Dk 2.20, Df 0.0010) is the F4B grade suited to wideband, low-loss applications — EW receivers, ESM systems, and antenna feed networks where minimizing insertion loss across the operating band is the primary requirement. Its Dk and Df values place it in a comparable performance tier to other low-Dk PTFE materials commonly used for this application space.
F4BM300 — general RF and filter design
F4BM300 (Dk 3.0, Df 0.0017) sits at a Dk value commonly used for X-band and Ku-band filter and antenna designs. This Dk tier balances trace width and physical element size for many general-purpose RF layouts.
F4BTM series — high-Dk miniaturization
F4BTM440 (Dk 4.40) and F4BTM615 (Dk 6.15) are specified when physical size reduction is the primary design driver. Higher Dk shrinks the electrical wavelength for a given physical dimension, useful for compact patch antenna elements and space-constrained phase shifter designs. These grades carry higher Df than the low-Dk F4BM series, a tradeoff inherent to high-Dk PTFE composites generally.
Manufacturing Requirements for F4B Materials
Like all PTFE-based RF substrates, F4B materials require in-house plasma hole wall activation before copper plating. See PTFE PCB manufacturer for the plasma activation process and timing requirements. F4B materials follow the same 2-cycle maximum lamination limit as other PTFE substrates including Rogers RO3003/RT5880 and Taconic grades.
Design Considerations When Specifying F4B Materials
- Confirm Dk value used in impedance simulation matches the actual material certificate for your production lot — F4B datasheet Dk values are nominal, actual lot Dk may vary within the stated tolerance
- Specify plasma activation and lamination cycle requirements explicitly on the fabrication drawing
- For hybrid stackups combining F4B PTFE layers with FR4, confirm compatible bonding film with your fabricator
Material Availability at Riching PCB
Riching PCB maintains a materials library covering Rogers, Taconic, F4B and other RF laminate brands — see Taconic PCB material guide for the equivalent reference on Taconic grades. Confirm specific grade, thickness and quantity requirements for current stock status and lead time.
F4B PCB Materials — Q&A
Common questions about F4B material grades, Dk/Df properties, applications and manufacturing process requirements.
What is F4B PCB material?
F4B is a PTFE-based RF laminate family produced by Wangling. The range spans low-Dk grades (F4BM220, Dk 2.20) through mid-Dk (F4BM300, F4B350) to high-Dk miniaturization grades (F4BTM440, F4BTM615). All grades require in-house plasma hole wall activation like other PTFE substrates.
What is F4BM220 used for?
F4BM220 (Dk 2.20, Df 0.0010) is the lowest-loss F4B grade, used for wideband low-loss applications including EW receivers, ESM systems, and antenna feed networks — comparable performance tier to other low-Dk PTFE materials.
Does F4B PCB material require plasma activation?
Yes. F4B materials are PTFE-based and require in-house plasma hole wall activation, the same as other PTFE substrates, and follow the same 2-cycle maximum lamination limit.
What thicknesses are available for F4B PCB material?
F4B grades are generally available across 0.127mm to 3.0mm, with custom thicknesses on request. Confirm specific grade and thickness with your fabricator for current stock and lead time.
F4B, Taconic and Rogers — Full RF Material Library
In-house plasma activation for all PTFE materials. Confirm grade, thickness and quantity for current stock status and lead time. No MOQ. TDR impedance verification available.
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