Four grades, one platform: how Dk moves from 3.00 to 3.40 across the series, and which parameter actually decides the choice.
The Taconic TLX series is built around a simple idea: one platform, several dielectric constants. Grades within the series share the same construction approach and differ mainly in Dk, so a designer can tune impedance and electrical length without changing material supplier, process route or qualification basis. The family is used across communications, aerospace, medical devices and radar systems. This article sets out the parameters for TLX-6, TLX-7, TLX-8 and TLX-9 and explains where the differences actually matter — for the wider brand picture, see our notes on Taconic laminate performance.
Three things move between grades: dielectric constant, dissipation factor and the position of the grade within the temperature range. The Dk spread is the important one, because it lets a designer reach a target impedance with a favourable trace width instead of shrinking lines to fit a fixed material. Df stays low across the series at around 0.003, rising slightly on TLX-9, and every grade operates from −55°C to +125°C, so the temperature envelope is a constant rather than a differentiator.
| Parameter | TLX-6 | TLX-7 | TLX-8 | TLX-9 |
|---|---|---|---|---|
| Dk at 10 GHz | 3.00 | 3.20 | 3.15 | 3.40 |
| Dissipation factor | ≈0.003 | ≈0.003 | ≈0.003 | ≈0.0035 |
| Temperature range | −55 to +125°C | −55 to +125°C | −55 to +125°C | −55 to +125°C |
| Thermal expansion | Low | Low | Lower than the other grades | Low |
| Typical use | Communications, radar, satellite links | Aerospace and military systems | High-integrity links and test instruments | Radar, satellite and microwave equipment |
The grades differ in degree rather than in kind, but the difference is enough to change which design each one suits.
At Dk 3.00 and Df around 0.003, TLX-6 is the lowest-constant grade in the series and the natural starting point for high-frequency work where delay matters. It handles the data rates and stability requirements of high-frequency communications, radar and satellite links, and its low loss keeps attenuation down in precision signal paths. Where a design needs the shortest electrical length available from this family, this is the grade.
TLX-7 raises Dk to 3.20. The slightly higher constant is useful when a design needs a particular trace geometry that a lower Dk would force too wide or too narrow, and it still suits most high-frequency applications with a similar Df of 0.003. Low thermal expansion keeps dimensions steady in variable temperature, which is why the grade appears in aerospace and military systems where stability under demanding conditions is the requirement.
TLX-8 sits at Dk 3.15 with balanced electrical behaviour, and it is the grade that suits the widest range of high-frequency work. Its dissipation factor is low enough to hold signal quality over long distances, and it has the lowest thermal expansion of the series, which helps in environments with high temperature and frequent cycling. High-integrity communications links and test instrumentation are its natural applications, because both depend on the signal arriving exactly as it left.
TLX-9 has the highest Dk in the series at 3.40, and a dissipation factor of 0.0035 — still low, but the only grade in the family where loss rises. The higher constant is the point: it allows physically shorter resonators and matching structures, which is useful in precision, high-reliability work such as radar, satellite communications and microwave equipment. It is the grade to choose when the circuit topology needs a higher dielectric constant rather than the lowest possible loss.
Start from the impedance target and the trace geometry it permits, then check that the resulting loss budget still closes. TLX-6 gives the lowest Dk and the shortest delay, TLX-8 the best balance with the tightest dimensional stability, and TLX-9 the highest Dk for compact high-reliability circuits. If the requirement instead leans toward a different balance of properties, the TLY-3 grade trades some Dk flexibility for a higher temperature ceiling, and RF-30 sits alongside at Dk 3.0 with ceramic filler. Our comparison of microwave substrate families puts all of these in context. Send us the stack-up and the frequency plan and we will confirm the grade.
Frequently Asked Questions
Mainly dielectric constant: 3.00, 3.20, 3.15 and 3.40 at 10 GHz. Loss stays near 0.003 across the family, and every grade shares a −55°C to +125°C operating range.
TLX-6, TLX-7 and TLX-8 are effectively equal at around 0.003. TLX-9 rises slightly to about 0.0035, which is the trade it makes for a higher Dk.
To shorten physical structures. A higher Dk allows more compact resonators and matching networks at the same frequency, which matters in dense, precision circuitry where space is the constraint.
No. All four grades operate from −55°C to +125°C, so the temperature envelope does not decide the selection; Dk, loss and thermal expansion behaviour do.
TLX spans Dk from 3.00 to 3.40 across several grades. TLY-3 emphasises a higher temperature ceiling, and RF-30 offers Dk near 3.0 with ceramic filler for mechanical stability.
Send us the impedance target and frequency plan and we will recommend the grade and confirm the stack-up is manufacturable.
Get Material Advice Fast Reply on WhatsApp