Taconic PCB Materials: TLY, RF Series and CER-10 Compared

Why the Material Family Matters

Taconic produces a range of PTFE based laminates for radio frequency and microwave work, and the families differ mainly in dielectric constant, loss and mechanical behaviour. Choosing among them is a question of matching the electrical requirement to the physical constraints: a low dielectric constant makes a wide trace for a given impedance, a higher dielectric constant shrinks a filter or an antenna but raises loss, and the mechanical properties decide whether the board can be processed and whether it stays flat. Knowing which family does what makes the selection a calculation rather than a guess.

TLY: Low Loss and Low Dielectric Constant

The TLY family is a PTFE based laminate with a low dielectric constant, typically around 2.2 to 2.3, and a very low loss tangent. Its low dielectric constant means that a 50 ohm line is wider than on a higher Dk material, which reduces conductor loss and makes the trace easier to etch accurately. The low loss makes it suitable for long transmission lines, antennas and filters where the loss budget is tight. It is commonly supplied with different copper foil options, and the choice of foil matters because surface roughness becomes a significant part of conductor loss at higher frequencies. TLY is often the default choice for microwave boards that need the lowest possible loss.

RF Series: Balanced Performance

The RF series covers a range of dielectric constants, typically from about 2.5 up to 4 or higher, achieved by changing the ceramic filler content in the PTFE. A mid range dielectric constant is useful because it allows a physically smaller circuit than a very low Dk material while keeping the loss moderate. That trade is valuable in filters and matching networks, where a higher dielectric constant shrinks the structure, and in antennas where the size has to fit a given enclosure. The family is generally easier to process than the lowest loss grades, and it is a common choice where the design needs a compromise between size, loss and cost.

CER-10: High Dielectric Constant for Compact Circuits

CER-10 is a ceramic filled PTFE laminate with a dielectric constant of about 10, which is far higher than the other families. The high dielectric constant makes transmission lines very narrow for a given impedance, which allows filters, couplers and matching networks to be built in a fraction of the area. That size reduction is the whole point: a quarter wave structure at a given frequency is roughly three times shorter on a Dk of 10 than on a Dk of 2.2. The trade is loss, because the loss tangent of a high Dk ceramic filled material is higher than the low loss grades, and the narrower traces make conductor loss more significant. CER-10 is therefore used where miniaturisation matters more than the last fraction of a decibel.

How They Compare

Dielectric constant. TLY is the lowest at around 2.2, the RF series spans the middle, and CER-10 is the highest at about 10. Loss. TLY and the low loss RF grades are the best, and CER-10 trades loss for size. Trace geometry. Lower Dk means wider traces, which are easier to etch and have lower conductor loss; higher Dk means narrower traces and a smaller circuit. Mechanical. All are PTFE based, so they are softer than FR4, prone to smearing when drilled and usually requiring plasma treatment before plating. Cost. Cost generally rises with the tightness of the electrical specification, and the high Dk material carries a premium for its ceramic content. Availability. All are stocked in standard thicknesses, but the exact construction affects the achievable tolerance.

Matching Material to Application

Antennas and long feeds. A low dielectric constant with low loss, so the TLY family is usually the right starting point. Filters and couplers with size constraints. A mid to high dielectric constant shrinks the structure, and the RF series or CER-10 becomes attractive. Radar and instrumentation front ends. Low loss across the band, so the lowest loss grade is chosen and the geometry is designed around it. Compact multi-band modules. High dielectric constant materials allow several structures in a small area, at the cost of some loss. In every case the decision should follow a calculated loss budget and a physical size constraint, not a preference for one family.

Processing Notes

All these laminates behave like other PTFE materials in the shop. They are softer than FR4, so drilling parameters have to be adjusted and the hole wall can smear; plasma treatment is the usual preparation before plating because the material is chemically inert. Their coefficient of thermal expansion is higher than FR4, so registration and press profiles need care, especially in a hybrid stack where they are bonded to a standard laminate. Copper foil choice is part of the electrical design, because smooth foils reduce conductor loss at high frequency. Finally, the dielectric constant varies slightly with the specific construction and thickness, so the value used for the impedance calculation should come from the supplier’s data for that exact build, and be verified with a test coupon.

RF material selection is a joint decision between the microwave engineer and the fabricator, because the achievable geometry depends on what the shop can build. Review how PCB manufacturing processes PTFE laminates, apply the transmission line rules in your PCB design and layout, and check the design and manufacturing considerations before release. A prototype PCB assembly run with a measured S parameter sweep confirms the material behaves as designed.

FAQ

Which Taconic material has the lowest loss? The TLY family, which combines a very low dielectric constant with a very low loss tangent.

Why would I choose a high dielectric constant material? To shrink filters, couplers and matching networks, accepting a slightly higher loss in exchange for size.

Do these materials need special processing? Yes. They are soft PTFE laminates that need tuned drilling and plasma treatment before plating.

Can the published dielectric constant be used directly? It should be confirmed for the specific construction and thickness, and verified with a coupon on the panel.

Conclusion

Taconic laminates span from very low loss, low dielectric constant materials for antennas and long feeds, through mid range grades for compact filters, to CER-10 with a dielectric constant near ten for aggressive miniaturisation. Choose by loss budget and size constraint, confirm the dielectric constant for the exact construction, and account for the PTFE processing requirements. Selected that way in 2026, the laminate will hold the impedance and meet the frequency response.