CLTE is a reinforced PTFE microwave laminate designed with dimensional and thermal behavior in mind. It can be useful for multilayer or mechanically demanding RF circuits where registration and stability are central requirements. The currently retrieved product sheet differs from the selector in several values, so this record follows the sheet's explicit observations.
Material system
Ceramic-filled, woven-glass-reinforced PTFE
Technical properties
| Property | Reported value | Conditions / source |
|---|---|---|
| Process dielectric constant | 2.98 | Typical; 10 GHz, 23°C/50% RH; IPC-TM-650 2.5.5.5 clamped stripline; direction is not separately recorded here. Source |
| Design dielectric constant | 2.98 | Typical; 10 GHz, microstrip differential phase length method, C-24/23/50 conditioning. Source |
| Dissipation factor | 0.0021 | Typical; 10 GHz, 23°C/50% RH; IPC-TM-650 2.5.5.5; direction is not separately recorded here. Source |
| Thermal conductivity | 0.5 W/(m·K) | Typical, through thickness; ASTM D5470. The product table does not state test temperature. Source |
| Thermal coefficient of dielectric constant | 6 ppm/°C | Typical; -50°C to 150°C, IPC-TM-650 2.5.5.5 (modified temperature measurement); 10 GHz. Source |
| Water absorption | 0.04 % | Typical; E1/105 + D24/23, IPC-TM-650 2.6.2.1. Source |
| Density | 2.31 g/cm³ | Typical; C-24/23/50, ASTM D792. 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 reliable alignment and controlled RF properties matter together, such as a multilayer feed network with repeated transitions. Compare the chosen core and bonding combination rather than expecting the core alone to determine multilayer performance.
- When evaluating CLTE-XT as an alternative, use the same geometry and environmental conditions. A lower Df in another grade may be valuable without establishing that it is the right mechanical or fabrication choice.
Thickness and copper options
The sheet lists 5.3, 10, 20 and 30 mil cores. Use the thickness-specific tolerance from the current offering table.
ED and reverse-treated copper are listed. The selected foil must be included in any comparison with CLTE-XT.
Fabrication considerations
- Work with a fabricator familiar with reinforced PTFE and agree panel compensation, drilling and bonding preparation. Inspect plated-hole quality and registration on the intended multilayer process, especially when thin cores are combined with numerous copper layers.
Application fit
- Dimensionally controlled RF boards
- PTFE multilayers
- Microwave feed networks
Limits and substitution checks
- The product sheet lists Df 0.0021 and a different temperature coefficient from the selector summary. Those differences are retained in the source report and status. Do not reuse an older CLTE material card without checking which document and construction it represents.