RO3010 + FR-4 Hybrid 4-Layer PCB with 1080 Prepreg for Microwave, Radar & Phased Array Applications

(Note: Printed Circuit Boards are custom-made products. Images and parameters are for reference only.)

1. Introduction to RO3010 Hybrid High Frequency PCB

Rogers RO3010 is a ceramic-filled PTFE composite laminate with a dielectric constant (Dk) of 10.2 ± 0.30 at 10GHz and a low dissipation factor (Df) of 0.0022, offering exceptional high-frequency performance. This material is ideal for commercial microwave and RF applications requiring high dielectric constant and stable electrical properties.

This 4-layer hybrid board combines two 1.27mm RO3010™ cores with a single sheet of 1080 FR-4 prepreg (0.076mm) in a symmetrical stackup. The symmetrical construction is specifically designed to minimize warpage caused by the CTE mismatch between the ceramic-filled PTFE cores and the FR-4 prepreg. The finished board is 2.8mm thick with 1oz copper on all layers and immersion tin surface finish.

2. Key Features of RO3010 Hybrid PCB

• Dielectric Constant (Dk): 10.2 ± 0.30 @ 10GHz (process)

• Design Dk: 11.20 (8 GHz - 40 GHz, differential phase length)

• Dissipation Factor (Df): 0.0022 @ 10GHz/23°C

• Thermal Coefficient of εr: -395 ppm/°C (-50°C to +150°C)

• High Thermal Conductivity: 0.95 W/m/K @ 50°C

• Low Moisture Absorption: 0.05%

• CTE: X/Y=13/11 ppm/°C, Z=16 ppm/°C (-55°C to 288°C)

• Decomposition Temperature (Td): 500°C

• Symmetrical 4-layer hybrid stackup

• Lead-Free Process Compatible, UL 94 V-0 flammability rating

• Excellent dimensional stability

3. Benefits of RO3010 Hybrid PCB

• High Dk (10.2±0.30) — Enables compact circuit designs with reduced physical dimensions

• Low Df (0.0022 @ 10GHz) — Minimal signal loss for RF and microwave applications

• Symmetrical Stackup — Minimizes warpage caused by CTE mismatch between RO3010 and FR-4

• CTE Matched to Copper — X/Y CTE of 13/11 ppm/°C ensures excellent dimensional stability

• High Thermal Conductivity (0.95 W/m/K) — Excellent heat dissipation for high-power applications

• 1080 Prepreg Selection — Thin, low-flow prepreg suitable for hybrid bonding

• Immersion Tin Finish — Excellent solderability and corrosion resistance

4. PCB Construction Details

5. PCB Stackup (4-Layer Hybrid Structure)

Layer 1 (Top): Copper, 35 μm (1 oz)

Dielectric: RO3010™ Core, 1.27 mm (Dk 10.2 ± 0.30 @ 10GHz)

Layer 2 (Inner): Copper, 35 μm (1 oz)

Prepreg: 1080 FR-4 PP, 0.076 mm

Layer 3 (Inner): Copper, 35 μm (1 oz)

Dielectric: RO3010™ Core, 1.27 mm (Dk 10.2 ± 0.30 @ 10GHz)

Layer 4 (Bottom): Copper, 35 μm (1 oz)

Total thickness: 2.8 mm

6. Technical Deep Dive: RO3010 + FR-4 Hybrid Stackup Design

6.1 4-Layer RO3010 + 1080 PP Hybrid Stackup Analysis: 1.27 + 0.076 + 1.27mm, 2.8mm Total Thickness Design Points

The stackup consists of two 1.27mm RO3010 cores bonded by a single 1080 FR-4 prepreg (0.076mm). This symmetrical construction (1.27 + 0.076 + 1.27mm) is critical for minimizing warpage. The total dielectric thickness before copper is 2.616mm, and with 1oz copper on all four layers (4 × 0.035mm = 0.14mm), the nominal finished thickness is approximately 2.756mm, which is rounded to 2.8mm in the design specification. The high Dk of RO3010 (10.2) allows for significant size reduction in RF circuits, while the thin 1080 prepreg provides a low-profile bond line with minimal impact on the overall electrical performance.

6.2 Rogers RO3010 and FR-4 PP Hybrid Lamination: 1080 Prepreg Selection and Lamination Risk Points

The 1080 prepreg is a critical choice for this hybrid stackup. With a nominal thickness of 0.076mm, it is thin enough to minimize the overall thickness contribution while still providing sufficient resin to bond the RO3010 cores. However, the 1080 prepreg has a relatively low resin content compared to thicker prepregs like 2116 or 7628, which can lead to insufficient flow and fill around heavy copper features. Lamination risks include:

• Resin starvation: The low resin content of 1080 may not fully fill the etched areas on the inner layers, leading to voids or delamination.

• Insufficient bonding: The PTFE surface of RO3010 is notoriously difficult to bond. Proper surface treatment (e.g., sodium etching) is required to achieve adequate peel strength.

• CTE mismatch: The CTE of RO3010 (13/11 ppm/°C) is significantly lower than that of FR-4 (typically 50-70 ppm/°C), creating stress at the interface during thermal cycling.

• Dimensional stability: RO3010 has a dimensional stability of -0.35/-0.31 mm/m, which must be considered when designing the artwork.

6.3 Heterogeneous Material Hybrid 4-Layer Board: CTE Matching Analysis of RO3010 Ceramic-Filled Substrate and FR-4 PP

The CTE mismatch between RO3010 and FR-4 is a major concern in hybrid designs. RO3010 has an X/Y CTE of 13/11 ppm/°C, while FR-4 typically has an X/Y CTE of 50-70 ppm/°C. This mismatch can cause significant stress at the bond line during thermal cycling, potentially leading to delamination or warpage. The Z-axis CTE of RO3010 is 16 ppm/°C, which is much lower than FR-4's Z-axis CTE of 50-60 ppm/°C. The thin 1080 prepreg (0.076mm) helps to minimize the overall CTE mismatch by reducing the volume of FR-4 in the stackup. Additionally, the symmetrical construction ensures that the CTE mismatch is balanced on both sides of the neutral axis, reducing warpage.

6.4 Symmetrical Stackup Improves Warpage of RO3010 Hybrid Board (Finished Thickness 2.8mm Example)

Warpage is a common problem in hybrid PCBs due to the CTE mismatch between different materials. In this 2.8mm thick example, the symmetrical stackup (1.27mm RO3010 + 0.076mm 1080 PP + 1.27mm RO3010) is essential for minimizing warpage. The neutral axis is located at the center of the 1080 prepreg, and the two RO3010 cores are identical in thickness and material properties. This symmetry ensures that the thermal expansion on both sides of the neutral axis is balanced, preventing the board from bowing or twisting during thermal cycling. Additionally, the thin 1080 prepreg minimizes the volume of FR-4, which is the primary source of CTE mismatch. Post-lamination cooling should be controlled to reduce residual stress.

6.5 1080-0.076mm PP for RO3010 High-Frequency Board: Resin Flow, Fill, and Interlayer Bonding Control

The 1080 prepreg is a thin, low-flow material that requires careful control of the lamination process to ensure proper resin flow, fill, and interlayer bonding. Key process parameters include:

• Resin flow: The 1080 prepreg has a resin flow of approximately 10-15%, which is lower than thicker prepregs. This means that the prepreg may not completely fill large etched areas, leading to voids. To mitigate this, the inner layer copper should be kept as thin as possible (1oz is used here) and the etch patterns should be designed to minimize large open areas.

• Fill: The 1080 prepreg must fill the gaps between the RO3010 cores and the copper features. Proper fill is essential for preventing delamination and ensuring reliable electrical performance.

• Interlayer bonding: The bond strength between the RO3010 cores and the 1080 prepreg is critical. The RO3010 surface must be properly treated (sodium etching) to promote adhesion. The lamination cycle should be optimized to ensure complete cure of the prepreg and maximum bond strength.

7. Rogers RO3010 – Product Introduction

RO3010™ is a ceramic-filled PTFE composite laminate offering a dielectric constant (Dk) of 10.2 ± 0.30 at 10GHz and a low dissipation factor (Df) of 0.0022. The material features a thermal coefficient of εr of -395 ppm/°C, ensuring stable electrical performance across a wide temperature range (-50°C to +150°C). With a thermal conductivity of 0.95 W/m/K and a decomposition temperature (Td) of 500°C, RO3010™ provides excellent thermal management for high-frequency applications.

The material exhibits outstanding dimensional stability with X/Y CTE of 13/11 ppm/°C and Z-axis CTE of 16 ppm/°C (-55°C to 288°C), closely matched to copper for reliable plated through holes. Its low moisture absorption (0.05%) ensures consistent electrical performance in humid environments.

Key Material Properties:

• Dk: 10.2 ± 0.30 @ 10GHz (process)

• Df: 0.0022 @ 10GHz/23°C

• TCDK: -395 ppm/°C (-50°C to +150°C)

• Thermal Conductivity: 0.95 W/m/K @ 50°C

• CTE X/Y: 13/11 ppm/°C, CTE Z: 16 ppm/°C (-55°C to 288°C)

• Td: 500°C

• Moisture Absorption: 0.05%

• Flammability: UL 94 V-0

• Lead-Free Process Compatible

8. Features and Benefits Summary

Feature	Benefit
Dk 10.2 ± 0.30 @ 10GHz	High dielectric constant for compact circuit designs
Df 0.0022 @ 10GHz	Low loss for high-frequency RF and microwave designs
TCDK: -395 ppm/°C	Stable performance across temperature
CTE: 13/11/16 ppm/°C	Excellent dimensional stability, reliable plated through holes
Td: 500°C	Exceptional thermal stability for demanding applications
Symmetrical Stackup	Minimizes warpage caused by CTE mismatch
1080 Prepreg	Thin bond line, minimal impact on electrical performance
Immersion Tin Finish	Excellent solderability and corrosion resistance

9. RO3010 Typical Properties (Data Sheet)

10. Primary Application Areas

• Microwave, RF, and radar systems

• Phased array antennas

• Band pass filters

• Microstrip patch antennas

• Voltage-controlled oscillators (VCOs)

• Satellite communications and base station antennas

• High-frequency RF and microwave circuits

11. Quality Assurance

• Type of artwork supplied: Gerber RS-274-X

• Accepted standard: IPC-6012 Class 3

• Availability: Worldwide

• 100% Electrical test prior to shipment

• ISO 9001:2015 & UL certified facility

12. Standard Thickness, Panel Sizes & Claddings

Parameter	Options
Standard Thicknesses (RO3010)	0.005" (0.13mm) ±0.0005", 0.010" (0.25mm) ±0.0007", 0.025" (0.64mm) ±0.0010", 0.050" (1.28mm) ±0.0020"
Standard Panel Sizes	12"x18" (305x457mm), 24"x18" (610x457mm), 24"x21" (610x533mm)
Electrodeposited Copper Foil	½ oz (18μm), 1 oz (35μm)