Both RO4350B hydrocarbon ceramic and RO4835 hydrocarbon ceramic belong to the RO4000 series of materials, which are designed for civilian applications. The RO4000 series consists of hydrocarbon resin and ceramic-filled laminate materials. These materials are compatible with FR-4 processing and mixed lamination processes, and they support lead-free soldering. This ensures that PCB manufacturers only require basic processing capabilities, which reduces the PCB manufacturing cost for customers.
Key Features of RO4000 Series
Low Loss: Dielectric loss (Df) of 0.0037 at 10GHz, ensuring excellent performance.
Stable Dielectric Constant: Exceptional temperature stability at 50 ppm/°C from -50°C to 150°C.
Better Heat Dissipation: Compared to traditional PTFE materials, the RO4000 series has improved thermal performance, with a thermal conductivity of 0.6 W/m/°K.
Low Z-Axis Thermal Expansion: At 31 ppm/°C, it improves through-hole reliability.
Superior Electrical Performance: The materials ensure the required performance for radar front-end and antenna systems operating at 24GHz.
Flame Retardancy: The materials comply with UL 94V-0 standards, further enhancing radar system safety.
Main Difference: RO4835 vs. RO4350B
The most significant difference between RO4835 and RO4350B is that RO4835 includes an antioxidant additive. Compared to conventional thermoset materials, RO4835 improves oxidation resistance by up to 10 times and meets the requirements of IPC-4103 (high-speed, high-frequency base material standard).
Advantages of RO4835
Improved Oxidation Resistance: The oxidation resistance of RO4835 is significantly stronger than that of RO4350B.
Enhanced Durability: It provides better stability and reliability over extended periods.
Dimensional Stability and Absorption: RO4835 exhibits superior dimensional stability, hardness, and moisture absorption.
Limitations of RO4835
Temperature Characteristics: While the dielectric constant (Dk) and dissipation factor (Df) remain comparable, the temperature characteristics of products with glass fiber are relatively inferior, making the material less suitable for applications with stringent temperature range requirements.
Z-Axis Expansion Coefficient: RO4835 has a higher thermal expansion coefficient in the z-axis, which limits the number of PCB layers that can be reliably achieved.
Phase Characteristics: The high-frequency phase characteristics are relatively poorer, making RO4835 less suitable for products requiring strict phase precision.
Application in 24GHz Security Radar Systems
The 24GHz security radar system operates at a frequency range of 24–24.25GHz with a bandwidth of 250MHz, using an FMCW (Frequency Modulated Continuous Wave) waveform. Due to the high frequency and short wavelength, the radar system’s RF front-end and antenna can only use high-frequency microwave materials. Additionally, the competitive nature of the security industry demands that these materials not only offer excellent performance but also remain cost-effective, delivering a high price-to-performance ratio.
To meet the demands of the 24GHz security radar market, Rogers, a globally renowned manufacturer of high-frequency microwave materials, offers RO4350B hydrocarbon ceramic and RO4835 hydrocarbon ceramic for different application scenarios.