Rogers High-Frequency Board
The Core Enabler of High-Speed, High-Reliability RF/Microwave Systems

一、What is a Rogers High-Frequency Board? Core Definition and Technical Orientation

Key Technical Orientation

• RF/microwave communication: Supporting 5G base stations, satellite communication, and Wi-Fi 7, focusing on low insertion loss and stable dielectric constant;
• Aerospace/defense: Used in radar systems, avionics, and missile guidance, requiring extreme temperature resistance (-55℃~200℃) and anti-radiation performance;
• Automotive electronics: Applied to ADAS (Advanced Driver Assistance Systems) radar (77/79 GHz) and vehicle-mounted 5G modules, emphasizing thermal conductivity and mechanical durability;
• Test & measurement: Serving as substrates for high-frequency test probes and signal generators, demanding ultra-high dielectric precision (dielectric constant tolerance ≤±0.02).

二、Core Performance Advantages: Why Choose Rogers High-Frequency Boards?

1. Ultra-Low Dielectric Loss (tanδ): Minimizing Signal Attenuation

• Rogers material performance: Typical products (such as RO4350B, RT/duroid 5880) have a tanδ of 0.0015~0.004 at 10 GHz, far lower than FR-4 (tanδ≈0.02 at 1 GHz). For example, in a 5G base station’s 3.5 GHz signal transmission (100mm path length), the signal loss of a Rogers RO4350B board is only 0.3 dB, while an FR-4 board’s loss exceeds 1.5 dB—this difference directly determines whether the signal can reach the receiving end with sufficient strength.
• Application value: In long-distance high-frequency transmission scenarios (such as satellite communication links), ultra-low loss ensures that the signal maintains high signal-to-noise ratio (SNR), avoiding data errors caused by attenuation.

2. Stable Dielectric Constant (Dk): Reducing Phase Distortion

• Rogers material advantages:
  • Narrow tolerance: Most Rogers materials have a Dk tolerance of ±0.02~±0.04 (e.g., RT/duroid 6002 has Dk=2.94±0.04 at 10 GHz), while FR-4’s Dk tolerance is ±0.2~±0.3—this precision is critical for high-frequency circuits (such as microstrip antennas) that require strict impedance matching (50Ω/75Ω);
  • Frequency stability: Dk changes minimally with frequency. For example, Rogers RO4835’s Dk varies by only 0.03 when the frequency increases from 1 GHz to 20 GHz, ensuring stable signal phase in multi-band communication systems (such as 5G NR’s 3.5 GHz/28 GHz dual bands);
  • Temperature stability: Dk has a low temperature coefficient (TCDk). In the range of -55℃~150℃, the Dk change rate of Rogers materials is ≤±5%, while FR-4’s Dk can change by ±15%—this stability ensures reliable operation of automotive radar and aerospace equipment in extreme temperature environments.

3. Excellent Thermal & Mechanical Performance: Adapting to Harsh Environments

• Thermal conductivity: Rogers high-thermal-conductivity materials (such as RO4830G2) have a thermal conductivity of 0.6 W/(m·K), 2~3 times that of FR-4 (≈0.25 W/(m·K)), enabling efficient heat dissipation of high-power components (such as power amplifiers, PA), preventing performance degradation due to overheating;
• Mechanical strength: The substrate has high flexural strength (≥200 MPa) and peel strength (≥1.8 N/mm for copper foil bonding), ensuring that the board does not crack or delaminate under vibration (automotive: 10~2000 Hz, 10 G acceleration) or thermal cycling (1000 cycles of -55℃~125℃);
• Moisture resistance: Rogers materials (such as RO4360) have a water absorption rate of ≤0.1% (after 24 hours of boiling water immersion), far lower than FR-4 (≤0.8%), avoiding dielectric performance degradation caused by moisture absorption in humid environments (such as marine radar).

4. Compatibility with Advanced Processes: Supporting High-Density Design

• Fine-line routing: Compatible with laser drilling (minimum hole diameter 0.1mm) and thin copper foil (12μm), enabling line widths/spacings of 30μm/30μm—meeting the layout requirements of high-frequency microstrip lines and coplanar waveguides (CPW);
• Multi-layer lamination: Supports 2~20-layer lamination, with strict control of layer-to-layer alignment (tolerance ≤±25μm) and dielectric thickness uniformity (tolerance ≤±5%), ensuring consistent impedance across layers;
• Integration with passive components: The substrate’s stable dielectric properties allow direct integration of passive components (such as inductors, capacitors) on the board (e.g., using the substrate as a dielectric for capacitors), reducing the size of high-frequency modules by 30%~50%.

三、Main Product Series of Rogers High-Frequency Boards: Matching Scenarios with Materials

1. RO4000 Series: The "Cost-Effective Leader" for Commercial RF Applications

2. RT/duroid Series: The "High-Performance Benchmark" for Microwave/Aerospace

3. ULTRALAM Series: The "High-Thermal Solution" for Power-Dense Applications

• Key Performance: Dk=3.0±0.04@10GHz, tanδ=0.0025@10GHz, thermal conductivity=1.0 W/(m·K) (2x higher than RO4000 series);
• Typical Applications: 5G massive MIMO base station power amplifiers, industrial microwave heaters, and high-power laser driver modules;
• Advantage: While maintaining high-frequency performance, it solves the "heat accumulation" problem of power components, extending the service life of devices by 50%~100%.

4. RO3000 Series: The "Thin-Substrate Expert" for Miniaturized Modules

• Key Performance: RO3010 has Dk=10.2±0.05@10GHz (high Dk for miniaturizing antennas), tanδ=0.003@10GHz; RO3035 has Dk=3.5±0.05@10GHz, tanδ=0.0018@10GHz;
• Typical Applications: Wearable health monitoring devices (24 GHz vital sign radar), IoT 5G micro-modules;
• Advantage: Thin substrate reduces module thickness (down to 0.1mm), and high Dk enables antenna miniaturization (antenna size reduced by 30% compared to low-Dk materials).

四、Key Design & Manufacturing Considerations for Rogers High-Frequency Boards

1. Design Considerations: Optimizing High-Frequency Performance

（1）Transmission Line Design: Ensuring Impedance Matching

• Impedance calculation: Use Rogers’ official impedance calculation tool (such as Rogers Impedance Calculator) to determine line width, substrate thickness, and copper foil thickness. For example, for a 50Ω microstrip line on RO4350B (thickness 0.762mm, copper foil 35μm), the line width should be 1.5mm—deviations of ±0.1mm will cause impedance fluctuations of ±3Ω, leading to signal reflection;
• Transmission line type: Choose microstrip lines for single-sided/double-sided boards (simple processing) or striplines for multi-layer boards (better shielding, reducing crosstalk). For ultra-high frequencies (≥20 GHz), use coplanar waveguides (CPW) to minimize radiation loss;
• Avoiding discontinuities: Reduce right-angle bends (use 45° bends or arcs) and sudden line width changes—these will cause impedance mutations and increase reflection. For example, a right-angle bend in a 28 GHz microstrip line can increase insertion loss by 0.2 dB.

（2）Thermal Design: Preventing Heat Accumulation

• Copper foil selection: Use high-conductivity rolled copper foil (conductivity ≥98% IACS) instead of electrolytic copper foil—improves heat dissipation and reduces skin effect loss at high frequencies;
• Thermal vias: For power components (such as PA chips), add thermal vias (diameter 0.3~0.5mm, pitch 1mm) under the component to connect to the bottom copper layer, enhancing heat conduction;
• Copper pouring: Pour copper on unused areas of the board (connected to ground) to increase heat dissipation area and reduce electromagnetic interference (EMI).

（3）Material Selection: Matching Scenarios

• Commercial products (5G base stations, Wi-Fi): Prioritize RO4000 series (cost-effective, easy to process);
• High-end microwave (satellite, radar): Choose RT/duroid series (ultra-low loss, stable Dk);
• Power-dense applications (high-power PA): Select ULTRALAM series (high thermal conductivity);
• Miniaturized modules (wearables): Opt for RO3000 series (thin substrate, high Dk for miniaturization).

2. Manufacturing Process Considerations: Ensuring Material Performance

（1）Lamination Process: Controlling Pressure & Temperature

• Temperature curve: Follow Rogers’ recommended lamination parameters. For example, RO4350B requires a heating rate of 1~2℃/min, a peak temperature of 180℃ (held for 90 minutes), and a cooling rate of ≤3℃/min—overheating will cause material decomposition, while too fast cooling will lead to internal stress and delamination;
• Pressure control: Lamination pressure should be 20~30 kg/cm²—insufficient pressure results in poor bonding between layers, while excessive pressure causes material extrusion and uneven thickness.

（2）Drilling & Plating: Avoiding Material Damage

• Drilling: Use carbide drills with a high helix angle (35°~40°) and slow drilling speed (5000~8000 rpm) to prevent PTFE-based materials (RT/duroid series) from "smearing" (melting and adhering to the drill bit), which blocks holes;
• Plating: For PTFE materials, pre-treat the hole wall with "sodium naphthalene etching" to increase roughness (Ra≥1.5μm), ensuring copper plating adhesion (peel strength ≥1.5 N/mm). Avoid over-etching, which will damage the substrate.

（3）Quality Inspection: Ensuring Performance Compliance

• Electrical testing: Measure dielectric constant (using resonant cavity method) and insertion loss (using vector network analyzer, VNA) to confirm compliance with material specifications;
• Mechanical testing: Check peel strength, flexural strength, and thermal cycling performance (100 cycles of -55℃~125℃) to ensure durability;
• Microscopic inspection: Use a metallographic microscope to observe the hole wall (no smearing, no cracks) and layer interface (no delamination), ensuring manufacturing quality.