RO4350B PCB 4-Layer 1.8mm High-Frequency Laminates for Cellular Base Station Antennas

1.Introduction to RO4350B

Rogers RO4350B materials are advanced, proprietary woven glass-reinforced hydrocarbon/ceramics that deliver electrical performance comparable to PTFE/woven glass while benefiting from the manufacturability of epoxy/glass.

RO4350B laminates offer precise control over dielectric constant (Dk) and sustain low loss using standard epoxy/glass processing methods. These laminates are available at significantly lower costs than traditional microwave laminates and do not require the specialized through-hole treatments or handling procedures typical of PTFE-based materials. Additionally, RO4350B materials are UL 94 V-0 rated, making them suitable for high-power RF designs and active devices.

The thermal coefficient of expansion (CTE) of RO4350B provides critical advantages for circuit designers. Its expansion coefficient closely matches that of copper, ensuring excellent dimensional stability, which is essential for mixed dielectric multi-layer board constructions. The low Z-axis CTE of RO4350B laminates guarantees reliable plated through-hole quality, even under severe thermal shock conditions. With a Tg of over 280°C (536°F), the expansion characteristics of RO4350B remain stable across all circuit processing temperatures.

2.Features of RO4350B

Dielectric Constant: DK 3.48 ±0.05 at 10 GHz/23°C
Dissipation Factor: 0.0037 at 10 GHz/23°C
Thermal Conductivity: 0.69 W/m/°K
CTE: X-axis 10 ppm/°C, Y-axis 12 ppm/°C, Z-axis 32 ppm/°C
High Tg Value: >280 °C
Low Water Absorption: 0.06%

3.Benefits

Ideal for multi-layer board (MLB) constructions
Processes similarly to FR-4 at reduced fabrication costs
Excellent dimensional stability
Competitively priced

4.PCB Stackup: 4-Layer Rigid PCB

Copper Layer 1: 35 µm
Rogers RO4350B Core: 0.762 mm (30 mil)
Copper Layer 2: 35 µm
Prepreg (RO4450F): 0.102 mm (4 mil)
Copper Layer 3: 35 µm
Rogers RO4350B Core: 0.762 mm (30 mil)
Copper Layer 4: 35 µm

5.PCB Construction Details

Board Dimensions: Stepped 4-layer RF PCB; Outline 1: 70 mm x 50 mm (1 PCS), Outline 2: 70 mm x 40 mm, ±0.15 mm
Minimum Trace/Space: 4/7 mils
Minimum Hole Size: 0.3 mm
Stepped Outline: Yes
Finished Board Thickness: 0.5 mm
Finished Copper Weight: 1 oz (1.4 mils) for outer layers
Via Plating Thickness: 20 µm
Surface Finish: Immersion Gold
Top Silkscreen: No
Bottom Silkscreen: No
Top Solder Mask: No
Bottom Solder Mask: No
Electrical Testing: 100% electrical test performed prior to shipment

6.PCB Statistics

Components: 9
Total Pads: 32
Through Hole Pads: 17
Top SMT Pads: 15
Bottom SMT Pads: 0
Vias: 23
Nets: 4

7.Artwork and Standards

Type of Artwork Supplied: Gerber RS-274-X
Accepted Standard: IPC-Class-2
Availability: Worldwide

8.Typical Applications

Cellular base station antennas and power amplifiers
RF identification tags
Automotive radar and sensors
LNBs for direct broadcast satellites