TMM 6 is a ceramic-filled thermoset grade that moves the TMM family into higher-permittivity microwave design. It provides a useful comparison point against RO3006, RO3206 and RO4360G2, which have similar process-Dk regions but different resin systems, Design Dk and fabrication needs.
Material system
Ceramic-filled thermoset polymer
Technical properties
| Property | Reported value | Conditions / source |
|---|---|---|
| Process dielectric constant | 6.00 ± 0.080 | Typical; 10 GHz, Z direction; IPC-TM-650 2.5.5.5. Test temperature is not stated in this datasheet row. Source |
| Design dielectric constant | 6.3 | Typical, 8–40 GHz; differential phase length method. Average across the common constructions in the cited datasheet. Source |
| Dissipation factor | 0.0023 | Typical; 10 GHz, Z direction; IPC-TM-650 2.5.5.5. Test temperature is not stated in this datasheet row. Source |
| Thermal conductivity | 0.72 W/(m·K) | Typical; 80°C, Z direction, ASTM C518; product datasheet thermal table. Source |
| CTE, X axis | 18 ppm/°C | Typical; 0°C to 140°C; ASTM E831 and IPC-TM-650 2.4.41, product datasheet. Source |
| CTE, Y axis | 18 ppm/°C | Typical; 0°C to 140°C; ASTM E831 and IPC-TM-650 2.4.41, product datasheet. Source |
| CTE, Z axis | 26 ppm/°C | Typical; 0°C to 140°C; ASTM E831 and IPC-TM-650 2.4.41, product datasheet. Source |
| Thermal coefficient of dielectric constant | -11 ppm/°C | Typical; -55°C to 125°C, IPC-TM-650 2.5.5.5 (modified temperature measurement); frequency not separately stated in this datasheet row. Source |
| Water absorption | 0.06 % | Typical; D24/23, 0.050 inch (1.27 mm) specimen, ASTM D570; product datasheet, not the selector's different moisture conditions. 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 compact distributed component benefits from a rigid thermoset substrate. Compare the complete filter or coupler response and manufacturing margin, not just the reduction in line length.
- Its relatively small negative dielectric temperature coefficient may be useful for stability studies. Account for physical expansion and coupling changes as well, especially in narrowband structures where several small effects can move the response.
Thickness and copper options
Use the selected TMM 6 thickness and tolerance for the design; avoid treating the family thickness list as a stock catalogue.
Copper construction should be matched in comparisons with high-Dk PTFE alternatives.
Fabrication considerations
- Discuss tooling wear, edge quality and hole preparation with a fabricator familiar with the TMM composite. If it is mounted or bonded to a carrier, verify the interface process and flatness before interpreting RF results as a material issue.
Application fit
- Compact couplers
- Microwave filters
- Thermoset RF modules
Limits and substitution checks
- The material does not inherit PTFE processing instructions merely because its Dk resembles a PTFE grade. Conversely, its thermoset character does not establish every FR4 fabrication parameter. A lower-loss or more stable result must be demonstrated in the intended circuit geometry and temperature range.