6-Layer Hybrid PCB with RO4003C and FR4 for Impedance Controlled High Frequency Applications

(PCBs are custom-made; images and parameters are for reference only)

Introduction

This 6-layer hybrid high-frequency PCB features a Rogers RO4003C (20mil) core combined with FR4 Tg170℃ material, delivering excellent high-frequency performance with cost efficiency. RO4003C offers low dielectric loss and stable Dk (3.38±0.05), making it ideal for RF, microwave, broadband, and high-speed digital applications. The stack-up includes blind vias (L1-L2, L5-L6) and precise impedance control (L2:50Ω, L6:100Ω).

Stack-up Details

Layer	Material	Thickness (mm)
L1 (Top Copper)	Copper 1oz	0.035
Core (RO4003C)	Rogers RO4003C 20mil	0.508
L2 (Inner Copper)	Copper 1oz	0.035
Prepreg 1080+2113	FR4 Tg170℃	0.176
L3 (Inner Copper)	Copper 1oz	0.035
Core FR4	FR4 Tg170℃	0.016
L4 (Inner Copper)	Copper 1oz	0.035
Prepreg 1080+2113	FR4 Tg170℃	0.176
L5 (Inner Copper)	Copper 1oz	0.035
Core FR4	FR4 Tg170℃	0.016
L6 (Bottom Copper)	Copper 1oz	0.035
Total Thickness (with copper)		~1.738mm

Features and Benefits

1) RO4003C has one of the lowest temperature coefficients of dielectric constant, ideal for temperature-sensitive applications;
2) Stable Dk over a broad frequency range (Dk 3.38±0.05, Df 0.0027@10GHz);
3) Hybrid stack-up combines high-frequency performance with FR4 cost benefits;
4) Blind vias enable higher routing density and HDI designs;
5) Strict impedance control (coplane differential 50Ω/100Ω) ensures signal integrity;
6) ISO9001, ISO14001, IATF16949, UL certified facility;
7) Prototype to mass production capability.

Applications

RF/microwave circuits, matching networks, broadband communications, radar data acquisition, spread spectrum systems, duplexers, test & measurement equipment.

Parameter & Data Sheet

RO4003C Material Introduction & Data Sheet Highlights

Rogers RO4000® series hydrocarbon ceramic laminates are designed for superior high frequency performance and low-cost circuit fabrication. RO4003C™ is a rigid, thermoset laminate that can be processed using standard FR-4 epoxy/glass processes, eliminating the need for specialized via preparation such as sodium etch. Key characteristics include:

• Dielectric Constant (Process Dk): 3.38 ± 0.05 @ 10 GHz (clamped stripline)
• Design Dk: 3.55 (average, 8–40 GHz differential phase length method)
• Dissipation Factor: 0.0027 @ 10 GHz / 0.0021 @ 2.5 GHz
• Thermal Coefficient of Dk: +40 ppm/°C (-50°C to 150°C)
• Tg: >280°C (TMA), Td: 425°C (TGA)
• CTE (X/Y/Z): 11 / 14 / 46 ppm/°C
• Moisture Absorption: 0.06% (48 hrs immersion, 50°C)
• Flammability: UL 94 V-0 (N/A for RO4003C per datasheet, but meets industry standards)
• Lead-Free Process Compatible: Yes

RO4003C laminates are offered in standard thicknesses including 0.008", 0.012", 0.016", 0.020", 0.032", and 0.060", with various panel sizes and electrodeposited copper foils (½ oz, 1 oz, etc.). The material's low Z-axis CTE ensures reliable plated through-hole quality even under severe thermal shock.

RO4003C Key Electrical Properties

Standard Thicknesses

Applications

RO4003C is widely used in RF/microwave circuits, matching networks, controlled impedance transmission lines, broadband systems, radar data acquisition, spread spectrum, duplexers, and high-speed digital designs. Its low loss and stable Dk over temperature and frequency make it an ideal substrate for demanding high-frequency applications.

Typical end-use products include:

• Microwave mixers and converters
• Radar and communication systems
• Test and measurement equipment
• Wireless infrastructure (5G, Wi-Fi)
• Automotive radar and sensors