RO4350B + RO3010 Hybrid PCB What Makes This 12-Layer High-Frequency Board Ideal for RF & Radar Applications?

Product Description

What is this hybrid PCB?

It is a 12-layer high-frequency circuit board that combines two complementary Rogers materials: RO4350B (hydrocarbon ceramic, Dk 3.48) and RO3010 (ceramic-filled PTFE, Dk 10.2). This hybrid approach allows designers to optimize different layers for different functions—RO3010 handles high-dielectric-constant antenna layers, while RO4350B provides low-loss RF layers with standard FR-4 processability .

 

 

What makes it unique?

The board uses a nickel-free EPIG surface finish (Palladium/Immersion Gold) instead of standard ENIG. This removes the nickel layer's ferromagnetic properties, reducing insertion loss above 24 GHz—critical for 77 GHz automotive radar and satellite communications .

 

 

Key Takeaways

For Designers	For Procurement Professionals
✅ RO3010 (Dk 10.2) – High Dk for compact antenna layers	✅ FR-4 compatible processing – RO4350B uses standard workflows
✅ RO4350B (Dk 3.48) – Low-loss RF layers, UL94 V-0 rated	✅ Lower cost – Hybrid approach saves vs. all-RO3010 stacks
✅ Nickel-free EPIG – 0.18 dB/in lower loss than ENIG above 24 GHz	✅ RO4450F prepreg – CTE-matched for reliable lamination
✅ Blind vias – 7 groups (1-2, 2-5, 2-6, 2-8, 1-9, 10-12, 3-12)	✅ V-0 rated – RO4350B and RO4450F are UL94 V-0
✅ CTE matched to copper – 10-17 ppm/°C, excellent dimensional stability	✅ Worldwide availability – Rogers materials are globally sourced
✅ 3.14 mm thickness – Rigid, high-layer-count construction	✅ Lead-free compatible – Supports 260°C reflow

 

 

1. Why a Hybrid Stackup?

When a PCB is built on dissimilar materials instead of one material throughout, it is called a hybrid PCB . This approach allows designers to partition electrical functions by material characteristics rather than forcing a single material to do everything.

 

 

In this design:

 

RO3010 handles the high-Dk antenna layers (Dk 10.2) – The high dielectric constant allows for compact patch antenna arrays and smaller circuit footprints .

 

RO4350B forms the intermediate RF layers (Dk 3.48) – It provides low-loss performance with standard FR-4 processability .

 

RO4450F prepreg bonds everything together – This dual-compatible resin system ensures reliable lamination between PTFE-based RO3010 and hydrocarbon-based RO4350B .

 

 

2. Material Overview

RO4350B – The Workhorse of the RO4000 Series

RO4350B is a hydrocarbon ceramic laminate designed for superior high-frequency performance with low-cost circuit fabrication. It can be fabricated using standard FR-4 processes—unlike PTFE materials that require sodium etch treatment .

 

Property	Value
Dielectric Constant (process)	3.48 ± 0.05 at 10 GHz
Design Dk	3.66 (8-40 GHz)
Dissipation Factor	0.0037 at 10 GHz
TCDk	+50 ppm/°C
CTE X/Y	10/12 ppm/°C
CTE Z	32 ppm/°C
Tg	>280°C
Td	390°C
UL Flammability	V-0
Thermal Conductivity	0.69 W/m·K
Moisture Absorption	0.06%

 

 

RO4350B is the go-to material for cost-sensitive RF designs that still need controlled impedance and low insertion loss . It is UL94 V-0 rated and fully compatible with lead-free processing.

 

 

RO3010 – High-DK PTFE-Ceramic Material

RO3010 is a ceramic-filled PTFE composite with a high dielectric constant of 10.2. It is designed for applications that require compact circuit footprints .

 

Property	Value
Dielectric Constant (process)	10.2 ± 0.30 at 10 GHz
Design Dk	11.20 (8-40 GHz)
Dissipation Factor	0.0022 at 10 GHz
TCDk	-395 ppm/°C
CTE X/Y	13/11 ppm/°C
CTE Z	16 ppm/°C
Td	500°C
UL Flammability	V-0
Thermal Conductivity	0.95 W/m·K
Moisture Absorption	0.05%

 

 

 

RO3010's high Dk allows significantly smaller circuit footprints—useful for compact couplers, filters, and phased-array feed networks where board real estate is tight . It is not a general-purpose material but is the right tool for miniaturization-driven designs.

 

 

RO4450F Prepreg

RO4450F is a halogen-free, high-Tg prepreg used in multilayer constructions to bond Rogers cores together or to bond Rogers layers to FR-4 in hybrid stackups . It is UL94 V-0 rated and ensures reliable lamination between different material families.

 

 

3. Complete PCB Specifications

Specification	Detail
Board Type	12-Layer Hybrid RF/Microwave PCB
Base Materials	RO4350B (top/bottom) + RO3010 (intermediate layers) + RO4450F Prepreg
Finished Board Thickness	3.14 mm
Board Dimensions	107 × 91.5 mm (2 pieces)
Finished Copper (Outer)	1 oz (35 µm)
Finished Copper (Inner)	0.5 oz (18 µm)
Surface Finish	EPIG (Nickel-free Electroless Palladium/Immersion Gold)
Top Solder Mask	Green
Bottom Solder Mask	Green
Top Silkscreen	White
Bottom Silkscreen	White
Blind Vias	1-2, 2-5, 2-6, 2-8, 1-9, 10-12, 3-12
IPC Classification	Class 2
Artwork Format	Gerber RS-274-X
Testing	100% Electrical Test (before shipment)

 

 

 

Hybrid Construction Benefits

The pairing of RO3010 and RO4350B is enabled by RO4450F's dual-compatibility resin system. The CTE of RO3010 (13/11 ppm/°C) and RO4350B (10/12 ppm/°C) are closely matched to standard copper foil, delivering post-etch dimensional shrinkage below 0.35 mm/m . Unlike full PTFE RO3000 multilayer boards, RO4350B intermediate layers use standard FR-4 workflows without sodium etch via treatment, cutting manufacturing cycle time by 30% and lowering total material cost by 22% versus all-RO3010 12-layer stacks .

 

 

Nickel-Free EPIG Finish Advantages

Conventional ENIG finish incorporates an electroless nickel barrier layer with ferromagnetic properties that introduce significant insertion loss above 24 GHz . This product's nickel-free EPIG deposits a thin palladium barrier directly onto copper, removing nickel-related RF attenuation. Comparative testing at 10–40 GHz demonstrates 0.18 dB/in lower insertion loss versus standard ENIG . This is critical for 77 GHz automotive radar and satellite communications.

 

The thin palladium-gold stack also minimizes conductor geometry buildup, supporting tight line-space HDI blind via routing without short-circuit risk .

 

Blind Via HDI Design

Seven groups of staggered blind vias eliminate long through-via stubs that create parasitic capacitance and inductance at millimeter-wave bands . Multi-stage blind via stacking separates top antenna layer interconnections from inner power/ground transitions, reducing RF signal path length by 40% compared to conventional through-via 12-layer boards .

 

 

Electrical & Thermal Stability

RO3010 features a Dk thermal coefficient of -395 ppm/°C while RO4350B delivers +50 ppm/°C Dk drift from -50°C to 150°C; the hybrid stackup's composite dielectric temperature response balances antenna resonant frequency drift and broadband transmission line impedance stability across automotive-grade operating ranges (-40°C to 125°C) . RO3010 thermal conductivity (0.95 W/m·K) provides superior heat dissipation for high-gain antenna patches, while RO4350B's 0.69 W/m·K thermal conductivity spreads power amplifier heat across inner ground planes .

 

 

Application Fields

• 5G Base Station Amplifiers
• Satellite Communications
• Millimeter-Wave Equipment
• Phased-Array Feed Networks
• GPS/GNSS Antennas

 

 

Q1: Why use a hybrid stackup instead of a single material?

A hybrid stackup partitions electrical functions by material characteristics. RO3010's high Dk (10.2) is used for compact antenna layers and miniaturized feed networks. RO4350B (3.48) provides low-loss RF layers with FR-4 processability, reducing cost. RO4450F prepreg bonds them reliably . The approach saves approximately 22% cost compared to an all-RO3010 12-layer board .

 

 

Q2: What is nickel-free EPIG finish and why does it matter?

EPIG (Electroless Palladium/Immersion Gold) replaces the nickel layer in standard ENIG with a thin palladium barrier. Nickel is ferromagnetic and introduces insertion loss above 24 GHz . The nickel-free finish delivers 0.18 dB/in lower loss than ENIG at 10–40 GHz while maintaining solder joint reliability and gold wire bond capability .

 

 

Q3: Are RO4350B and RO3010 UL94 V-0 rated?

Yes. RO4350B is UL94 V-0 rated . RO3010 is also V-0 rated . Note that RO4003C is not UL94 V-0 rated—if V-0 is a requirement, RO4350B is the correct choice .

 

 

Q4: How are RO4350B and RO3010 bonded together?

They are bonded using RO4450F prepreg, a halogen-free, high-Tg bonding material with dual-compatibility resin. RO4450F is designed specifically for multilayer constructions bonding Rogers cores together or bonding Rogers layers to FR-4 . It is UL94 V-0 rated and ensures CTE-matched lamination without thermal reliability issues .

 

 

Q5: What applications are blind vias used for in this design?

Seven groups of staggered blind vias (1-2, 2-5, 2-6, 2-8, 1-9, 10-12, 3-12) eliminate long through-via stubs that create parasitic capacitance and inductance at millimeter-wave bands. They reduce RF signal path length by 40% compared to conventional through-via 12-layer boards, improving filter stopband attenuation and antenna radiation efficiency .

 

 

Ready to Get Started?

This 12-layer RO4350B+RO3010 hybrid PCB can be manufactured with nickel-free EPIG finish and blind via structures.

 

 

Contact us today for:

Hybrid stackup design assistance

Material selection guidance (RO4350B, RO3010, RO4450F)

Impedance calculation and design support

PCB quoting and DFM review

Technical support for your specific application