IsoClad 933 is the higher-Dk companion to IsoClad 917 in the nonwoven random-glass PTFE family. It offers another electrical geometry for microwave and potentially conformal structures while retaining a nonwoven reinforcement approach. Material selection should couple RF requirements with the intended mechanical shape.
Material system
Nonwoven random-glass-fiber-reinforced PTFE
Technical properties
| Property | Reported value | Conditions / source |
|---|---|---|
| Process dielectric constant | 2.33 | Typical, 10 GHz, 23°C; IPC-TM-650 2.5.5.5 clamped stripline; direction is not separately recorded here. Source |
| Dissipation factor | 0.0016 | Typical, 10 GHz, 23°C; IPC-TM-650 2.5.5.5; direction is not separately recorded here. Source |
| Thermal conductivity | 0.263 W/(m·K) | Typical; ASTM E1225, 100°C. 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
- Compare it with IsoClad 917 when a slightly smaller electrical structure or different feed width fits the assembly. Model the final shape and nearby conductors rather than assuming a flat-board calculation predicts a curved antenna.
- For a one-time formed circuit, determine allowable copper strain and mounting stability with the fabricator. Those mechanical limits may matter more to success than the small difference in nominal dielectric constant.
Thickness and copper options
Confirm the chosen dielectric thickness and forming constraints with the supplier and fabricator.
Retain the actual foil weight and treatment in both RF calculations and mechanical forming reviews.
Fabrication considerations
- Define whether fabrication precedes or follows forming, and how plated holes, copper patterns and attachments are supported. PTFE processing and forming instructions are separate requirements and should both be reviewed for the selected core and foil.
Application fit
- Conformal microwave circuits
- Curved antenna substrates
- Low-Dk RF structures
Limits and substitution checks
- The laminate's nonwoven reinforcement is not proof of unlimited flexibility or repeated-bend reliability. Its thermal-conductivity method and temperature differ from many other entries. A supplier replacement by a woven-glass grade with the same nominal Dk still needs mechanical and electrical validation.