Rogers RO3003™ high-frequency laminate with TG170 FR-4 materials 4 layer hybrid PCB for RF and microwave

4-Layer Hybrid High-Frequency PCB with RO3003™

1. Product Overview

This product is a 4-layer hybrid printed circuit board designed for demanding RF and microwave applications. It combines a Rogers RO3003™ high-frequency laminate with TG170 FR-4 materials to achieve an optimal balance between electrical performance, mechanical stability, and cost-effectiveness. The board measures 52 mm x 77 mm and is supplied as a single piece.

The outer layer utilizes RO3003—a ceramic-filled PTFE composite—to ensure superior signal integrity at high frequencies, while the inner FR-4 layers provide structural rigidity. The bottom side features no solder mask to facilitate optimal grounding or thermal dissipation, while the top side includes a green solder mask without lettering to protect RF traces. Immersion silver is used as the surface finish to minimize high-frequency signal loss.

2. Product Specifications

Stack-Up Structure

3. RO3003™ Laminate: Introduction & Key Properties

RO3003™ is a ceramic-filled PTFE composite from Rogers Corporation’s RO3000® Series, specifically engineered for commercial microwave and RF applications. Unlike glass-reinforced PTFE materials, RO3003 uses a unique ceramic filler system that provides exceptional electrical and mechanical stability without the variability introduced by woven glass.

According to the RO3000 Series Datasheet, RO3003 offers:

Dielectric Constant (Dk): 3.00 ± 0.04 at 10 GHz — tight tolerance ensures consistent impedance control.

Dissipation Factor (Df): 0.0010 at 10 GHz — very low loss, ideal for sensitive receiver paths.

CTE (X/Y axis): 17 ppm/°C — closely matched to copper, providing excellent dimensional stability and etch shrinkage below 0.5 mils/inch.

CTE (Z axis): 25 ppm/°C — ensures reliable plated through-holes (PTH) even under severe thermal cycling.

Thermal Coefficient of Dk: -3 ppm/°C — very stable over temperature (-50 to 150°C).

Lead-Free Process Compatible: Yes — withstands RoHS-compliant assembly temperatures.

4. Application Areas

The combination of RO3003 on the outer layers and TG170 FR-4 on the inner layers makes this PCB suitable for:

5G Infrastructure: Sub-6 GHz and mmWave antennas, base station power amplifiers, backhaul radios.

Automotive Radar: 77 GHz ADAS (Adaptive Driver Assistance Systems) — low loss and tight Dk tolerance enable accurate distance and velocity detection.

Aerospace & Defense: Phased array radars, satellite transceivers (SatCom), electronic warfare systems.

Test & Measurement: High-frequency probes, VNA calibration standards.

High-Speed Digital: 100G/400G/800G optical transceivers, data center switches.

5. Fabrication Notes

As noted in Rogers’ Fabrication Guidelines for RO3000 Series, standard PTFE processing techniques apply with minor modifications:

Drilling: Use carbide or diamond-coated bits with entry/exit supports to prevent smearing.

Desmear / Hole Preparation: Plasma etching or sodium naphthalene treatment is required to activate the PTFE surface for reliable copper plating.

Baking: Pre-bake at 120–150°C for 1–2 hours before lamination.

Solder Mask: Use high-adhesion, PTFE-compatible inks.

Handling: Avoid scratching the soft PTFE surface.

6. Summary

This 4-layer hybrid PCB leverages the low-loss, stable-Dk properties of RO3003 on the outer layers and the mechanical rigidity and cost-effectiveness of TG170 FR-4 on the inner layers. With immersion silver finish, selective solder mask, and a compact 52 mm x 77 mm footprint, it is an excellent choice for mixed-signal designs requiring both high-frequency performance and structural reliability.