CLTE-MW is a reinforced PTFE laminate offered in thin constructions for microwave and millimeter-wave interconnects. Its process and Design Dk depend on thickness, and the Design Dk construction table identifies the copper used for characterization. It is therefore better represented by a selected construction than by one universal number.
Material system
Ceramic-filled, woven-glass-reinforced PTFE
Technical properties
| Property | Reported value | Conditions / source |
|---|---|---|
| Dissipation factor | 0.0015 | Typical; 10 GHz, 23°C/50% RH; IPC-TM-650 2.5.5.5; direction is not separately recorded here. Source |
| Thermal conductivity | 0.42 W/(m·K) | Typical, through thickness; ASTM D5470. The product table does not state test temperature. Source |
| Process dielectric constant | 2.94–3.02 ± 0.04 | Typical; 10 GHz, 23°C/50% RH, IPC-TM-650 2.5.5.5. Thickness-dependent range; select the construction table before use. Source |
| Design dielectric constant | 3.03–3.10 | Typical; 8–40 GHz, C-24/23/50, microstrip differential phase length method. The page 4 construction table specifies AH/AH copper. Source |
| Thermal coefficient of dielectric constant | -35 ppm/°C | Typical; 0°C to 100°C, IPC-TM-650 2.5.5.5 (modified temperature measurement); 10 GHz. Source |
| Water absorption | 0.03 % | Typical; E1/105 + D48/50, IPC-TM-650 2.6.2.1. Source |
Typical reported values are not a purchase specification. Process Dk, design Dk and values measured at different frequencies are not interchangeable.
Selection and design notes
- Consider it when a thin dielectric and controlled mechanical handling are useful for high-frequency multilayers. Determine the necessary line width and copper thickness first, then select a core that keeps the geometry within fabrication capability.
- For a material comparison, keep copper and field geometry consistent. The Design Dk range reflects construction effects and must not be treated as random tolerance around one arbitrary midpoint.
Thickness and copper options
The product table covers nominal cores from 3 to 10 mil with construction-dependent Dk and tolerances.
The Design Dk table references AH/AH cladding; distinguish rolled, reverse-treated and other low-profile offerings.
Fabrication considerations
- Coordinate the PTFE core process with the selected prepreg or bondply, and verify pressed spacing between conductors. Spread reinforcement can help address local structure, but trace placement and actual glass/copper construction still deserve review for skew-sensitive or phase-matched paths.
Application fit
- Thin microwave multilayers
- Millimeter-wave feeds
- Low-skew interconnect studies
Limits and substitution checks
- Automatic Dk entry is disabled because the generic grade spans multiple thicknesses. The current table gives Design Dk over 8–40 GHz; it is not direct proof of one fixed permittivity at every millimeter-wave frequency. Validate the intended structure with appropriate RF coupons.