DiClad 880-IM applies the IM copper construction to a low-Dk woven-glass PTFE antenna substrate. It offers a different electrical geometry from the AD-based IM variants, and the product table also reports mechanical and thermal values that differ from ordinary DiClad 880. It must therefore remain a separate material record.
Material system
Woven-glass-reinforced PTFE with IM copper cladding
Technical properties
| Property | Reported value | Conditions / source |
|---|---|---|
| Dissipation factor | 0.0009 | Typical; 10 GHz, 23°C/50% RH; IPC-TM-650 2.5.5.5; direction is not separately recorded here. Source |
| Thermal conductivity | 0.23 W/(m·K) | Typical, through thickness; ASTM D5470. The product table does not state test temperature. Source |
| Process dielectric constant | 2.17 or 2.20 | Typical; 10 GHz, 23°C/50% RH, IPC-TM-650 2.5.5.5; two grade variants in IM datasheet. Source |
| Design dielectric constant | 2.2 | Typical; 10 GHz, C-24/23/50, microstrip differential phase length method; do not silently match to an unspecified process-Dk variant. Source |
| CTE, X axis | 28 ppm/°C | Typical; -55°C to 288°C, IPC-TM-650 2.4.41; average expansion over the interval, not necessarily linear. Source |
| CTE, Y axis | 49 ppm/°C | Typical; -55°C to 288°C, IPC-TM-650 2.4.41; average expansion over the interval, not necessarily linear. Source |
| CTE, Z axis | 317 ppm/°C | Typical; -55°C to 288°C, IPC-TM-650 2.4.41; average expansion over the interval, not necessarily linear. Source |
| Thermal coefficient of dielectric constant | -160 ppm/°C | Typical; 0°C to 100°C, IPC-TM-650 2.5.5.5 (modified temperature measurement); 10 GHz. Source |
| Water absorption | 0.02 % | Typical; E1/105 + D48/50, IPC-TM-650 2.6.2.1; 60 mil reference construction. 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 low permittivity and a low-PIM cladding approach fit the antenna dimensions. Compare the required line width and dielectric thickness with AD255C-IM before choosing a construction for a large feed panel.
- For an existing DiClad 880 design, measure a representative feed after the cladding change. Similar Df does not prove unchanged phase or loss when foil interface and manufacturing details differ.
Thickness and copper options
30 and 60 mil offerings are listed in the IM sheet. Confirm the dielectric variant as well as nominal thickness.
Specify the 35 µm IM ED cladding explicitly. Standard DiClad ED copper is not an equivalent IM construction.
Fabrication considerations
- Have the fabricator review the actual IM core and PTFE process, including drilling and plated-hole preparation. Use mechanical supports and panel controls suitable for the selected low-Dk reinforced construction, especially where a large antenna board must remain flat.
Application fit
- Low-Dk low-PIM antennas
- Wide-feed antenna boards
- Printed antenna arrays
Limits and substitution checks
- The process table lists 2.17 and 2.20 variants, and the reported expansion differs from the ordinary DiClad record. Automatic presets are withheld until the ordered variant is confirmed. PIM observations remain tied to the specific foil, thickness and two-tone test rather than a finished-antenna warranty.