CLTE-AT is a reinforced PTFE antenna and microwave substrate with low in-plane and through-thickness expansion in the published material table. It can be relevant when a larger RF structure must retain registration and geometry through manufacture and temperature changes. Its thermal measurement method differs from several other CLTE grades.
Material system
Ceramic-filled, woven-glass-reinforced PTFE
Technical properties
| Property | Reported value | Conditions / source |
|---|---|---|
| Process dielectric constant | 3 | Typical; 10 GHz, 23°C/50% RH; IPC-TM-650 2.5.5.5 clamped stripline; direction is not separately recorded here. Source |
| Dissipation factor | 0.0013 | Typical; 10 GHz, 23°C/50% RH; IPC-TM-650 2.5.5.5; direction is not separately recorded here. Source |
| Thermal conductivity | 0.64 W/(m·K) | Typical; ASTM E1461, through-thickness direction; test temperature not specified in the product table. Source |
| Thermal coefficient of dielectric constant | -10 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 + D24/23, 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
- Evaluate it for antenna feeds or multilayers where dimensional behavior deserves more weight than a simple Df ranking. Consider the full copper and bond-layer architecture because their expansion and stiffness contribute to the final board response.
- For a phase-matched network, compare dielectric temperature drift and physical expansion together. A stable substrate does not automatically compensate the connectors, enclosure or mounting points.
Thickness and copper options
The product sheet lists thin cores through 60 mil; obtain the actual nominal thickness and tolerance before defining impedance.
Specify the copper cladding and weight; no single roughness claim applies to every CLTE-AT order.
Fabrication considerations
- Ask the fabricator to demonstrate its reinforced-PTFE drilling and bonding process on the proposed stackup. Thin-core handling, registration and hole preparation should be discussed before routing a tightly toleranced multilayer feed.
Application fit
- Antenna feed networks
- Dimensionally stable RF layers
- PTFE multilayers
Limits and substitution checks
- The thermal-conductivity value is reported using ASTM E1461, not a universal method shared with all CLTE data. A grade chosen for dimensional stability may still need separate RF loss and moisture validation. Published application labels do not establish aerospace, defense or antenna-system qualification.