RO4835 is a hydrocarbon thermoset laminate developed with improved resistance to oxidative aging. It is relevant when a familiar RO4000 manufacturing route must also support long exposure at elevated temperature. Its headline dielectric values resemble RO4350B, but that similarity should be interpreted alongside aging requirements and construction details.
Material system
Ceramic-filled hydrocarbon thermoset reinforced with woven glass
Technical properties
| Property | Reported value | Conditions / source |
|---|---|---|
| Process dielectric constant | 3.48 ± 0.05 | Typical, 10 GHz, 23°C; IPC-TM-650 2.5.5.5 clamped stripline; thickness direction. Source |
| Design dielectric constant | 3.66 | Typical, 8–40 GHz; differential phase length method. Average across the common constructions in the cited datasheet. Source |
| Dissipation factor | 0.0037 | Typical, 10 GHz, 23°C; IPC-TM-650 2.5.5.5; thickness direction. Source |
| Thermal conductivity | 0.66 W/(m·K) | Typical; ASTM C518, 80°C; through-thickness thermal conduction. 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 lifetime drift is a more important selection criterion than a small room-temperature Df difference. Define the operating temperature, exposure duration and allowable frequency or impedance movement before choosing an aging test.
- When evaluating replacement of RO4350B, retain a common geometry and foil so that electrical differences can be separated from manufacturing variation and surface-roughness effects.
Thickness and copper options
Standard thicknesses follow the RO4000-style core offerings; a LoPro or RO4835T construction requires its own thickness table.
ED and LoPro variants are distinct. Use CU4000 documentation when specifying foil lamination in a compatible multilayer.
Fabrication considerations
- Use the RO4000 fabrication guidance and qualify the intended bonding materials for the full multilayer process. Track thermal history through lamination, assembly and rework, because an improved oxidation formulation does not remove the need to control processing exposure.
Application fit
- Thermally exposed RF boards
- Power-amplifier networks
- Long-life microwave equipment
Limits and substitution checks
- Improved oxidation resistance is not immunity to dielectric aging. The product datasheet still requires design-specific lifetime evaluation. LoPro and thin variants also have their own construction data; the base RO4835 scalar values must not stand in for every member carrying the same numerical prefix.