RF-35’s Dk, loss, CTE and temperature range in one place, where that balance of properties is used, and how the material is produced and controlled.
Taconic RF-35 is a high-frequency laminate used in communications, satellite links, radar, aerospace and automotive electronics. Its appeal is a balance rather than an extreme: a moderate dielectric constant that keeps circuit dimensions workable, low dielectric loss, a wide operating temperature range and enough mechanical strength to survive normal processing. For designs that need predictability across temperature and frequency but do not need the absolute lowest loss available, it is a practical choice. This article covers the parameters, the applications and how the material is produced.
The figures below are the ones that appear in most design reviews. A Dk of 3.48 sits in the middle of the high-frequency range, which is a deliberate position: low enough to keep loss and delay reasonable, and high enough that a given electrical length does not demand an impractically large board. The Df of around 0.003 is low but not the lowest available, so RF-35 is normally chosen where temperature range and mechanical stability matter as much as attenuation. The temperature range extends well beyond typical commercial requirements, which is why aerospace and military work features so heavily in its applications.
| Parameter | Value |
|---|---|
| Dielectric constant (Dk) | 3.48 @10 GHz |
| Dissipation factor (Df) | ~0.003 |
| Coefficient of thermal expansion | Low; minimal dimensional change with temperature |
| Operating temperature range | -55°C to +125°C |
| Dielectric thickness | 0.2 mm to 1.5 mm, customisable |
The application list follows from the combination of moderate loss and wide temperature tolerance.
RF-35 sits alongside other grades in the same manufacturer’s range, and the wider family comparison appears in our notes on Taconic high-frequency laminate performance.
The material is a composite rather than a single polymer, and that composition is what produces its balance of properties.
RF-35 combines ceramic filler, resin and glass fibre. The ceramic phase carries most of the responsibility for electrical performance, while the resin and glass fibre provide mechanical strength and thermal resistance. The result is a laminate that holds its electrical values across temperature while still being strong enough to process and machine without special handling. The same composite philosophy appears in the RF-30 material description, where the filler load is set for a different point on the same trade-off.
Manufacture uses lamination technology controlled for both temperature and pressure, and that control is what produces uniformity within a panel and repeatability between panels. For an RF material, panel-to-panel consistency is the property that matters most, because it is what allows a design validated on one board to work on the next one.
Each production batch is tested for dielectric constant, dissipation factor, temperature range and mechanical strength, which is the practical basis of the data sheet. RF-35 is also offered with customisation on thickness, panel size and other properties, so a design that needs a specific dielectric height is not forced to work around a catalogue value. Where the design instead needs a thinner build or a different thermal profile, the TLY-3 grade is a useful comparison point, and the broader survey of microwave materials puts both in context.
RF-35 is best understood as a balanced material. It offers a moderate Dk that keeps layouts practical, a low dissipation factor, a wide temperature range and a low coefficient of thermal expansion, without pushing any single parameter to its limit. For satellite and radar work, aerospace equipment and automotive radar, that combination is usually the right answer. Where the design instead needs the lowest possible loss, or the smallest possible circuit, another grade will fit better, and the material family is broad enough that the right one exists.
Frequently Asked Questions
A dielectric constant of 3.48 and a dissipation factor of around 0.003, both quoted at 10 GHz. That places it in the middle of the high-frequency range rather than at either extreme.
From -55°C to +125°C, which is wider than most commercial requirements and is the main reason satellite, aerospace and military applications feature so heavily in its use.
Because mechanical movement becomes an electrical problem. If the board expands differently from the copper bonded to it, dimensions shift with temperature, which changes impedance and makes performance less predictable.
A composite of ceramic filler, resin and glass fibre. The ceramic phase dominates the electrical performance while the resin and glass provide strength and thermal resistance.
Yes. RF-35 is offered from about 0.2 mm to 1.5 mm, and customisation extends to panel size and other properties, so a design is not restricted to catalogue values.
Send us your frequency band, thickness requirement and thermal range and we will confirm the grade and the stack-up before the build is scheduled.
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