UGPCB 6‑Layer Communication High Frequency Hybrid PCB – Ro4350B+FR4 Mixed Dielectric RF Board

When digital and RF systems push beyond multiple GHz, conventional PCB 재료 hit bottlenecks in signal integrity, 열 안정성, 그리고 임피던스 제어. UGPCB’s communication high frequency hybrid PCB solves these challenges.

1. 제품개요

제품명: UGPCB 6‑Layer Communication High Frequency Hybrid PCB
모델: UG‑HYBRID‑6L‑RF01
주요 사양: 6 레이어 / Ro4350B+FR4 mixed dielectric / 1.6mm 보드 두께 / 210mm × 280mm size / ENIG 표면 마감 / minimum mechanical drilled hole 0.25mm
포지셔닝: A cost‑effective interconnect solution for RF front‑ends and high‑speed digital mixed circuits. By placing Rogers RO4350B high‑frequency laminate on the top RF signal layers and FR-4 on the bottom power/ground and low‑speed digital layers, this design balances signal integrity, 열 안정성, 그리고 제조비용.

2. Definition – What is a High Frequency Hybrid PCB?

에이 high frequency hybrid PCB (also called mixed dielectric multilayer board) uses two or more materials with different dielectric properties in one 다층 인쇄 회로 보드.

This 6‑layer hybrid PCB has the following stackup:

층	기능	재료	주요 매개변수
L1	RF signal	RO4350B (0.2mm)	Dk=3.48±0.05@10GHz, DF = 0.0037
L2	RF ground	RO4350B	Low‑loss reference plane
L3	High‑speed digital	RO4450™ bondply + FR-4	Transition, 임피던스 매칭
L4	Power plane	FR-4	높은 Tg, 저렴한 비용
L5	Digital signal	FR-4	Standard epoxy glass
L6	Digital ground	FR-4	Mechanical support and heat dissipation

“Mixed dielectric construction significantly reduces cost – using high‑frequency material only on the layers that carry RF signals, and FR‑4 for the rest.”

3. 설계 지침

3.1 Critical Material Parameters

This product uses 로저스 RO4350B (ceramic‑filled hydrocarbon laminate) and FR‑4. Key RO4350B specifications (source: Rogers data sheet):

매개 변수	전형적인 가치	테스트 조건	참조
Process Dk	3.48± 0.05	10GHz	IPC‑TM‑650 2.5.5.5
Design Dk	3.66	10GHz	Copper roughness correction
소산 인자 (Df)	0.0037	10GHz	Low‑loss RF applications
Z‑axis CTE	32 ppm/℃	-55℃ to 288℃	Matches copper (17 ppm/℃)
열전도율	0.69 w/m · k	50℃, ASTM D5470	Better than FR‑4
가연성	UL 94 V‑0	UL standard	For active and high‑power RF

데이터 소스: Rogers Corporation RO4350B™ Laminate Data Sheet

3.2 임피던스 제어

Impedance control on a 6‑layer hybrid PCB is challenging because of the Dk discontinuity. Use a 3D electromagnetic solver and apply a copper roughness correction factor (typically 1.2–1.5). According to IPC‑2141A, characteristic impedance tolerance for RF PCBs should be within ±7%. UGPCB achieves ±5%.

3.3 Laminate Stackup Design (Total thickness 1.6mm)

• 맨 위 (L1‑L2): RO4350B 0.2mm × 2 = 0.4mm
• Middle (L3): RO4450™ prepreg 0.1mm + FR‑4 core 0.6mm = 0.7mm
• Bottom (L4‑L6): FR‑4 core + prepreg = 0.5mm
• Total: 1.6mm

Use a dynamic pressure curve during lamination to manage stress from CTE mismatch between RO4350B and FR‑4.

4. 작동 원리

신호 무결성: Dielectric loss dominates high‑frequency loss. The medium attenuation constant is:

${\mathrm{에이}}_{디}\approx 27.3\times \frac{\text{√}{\mathrm{이자형}}_{\mathrm{아르\; 자형}}}{{\mathrm{<span\; class="tr\_"\; id="tr\_79"\; data-source="0"\; data-orig="\lambda ">\lambda </span>}}_0}\times 티\mathrm{에이}N디(디비\mathrm{/}유N나티\mathrm{<span\; class="tr\_"\; id="tr\_80"\; data-source="0"\; data-orig="l">l</span>}\mathrm{이자형}Ng티\mathrm{시간})$

어디:

• ${\mathrm{에이}}_{디}$ = dielectric attenuation constant
• ${\mathrm{이자형}}_{\mathrm{아르\; 자형}}$ = 상대 유전율 (design value)
• ${\mathrm{<span\; class="tr\_"\; id="tr\_83"\; data-source=""\; data-orig="\lambda ">\lambda </span>}}_0$ = free‑space wavelength
• $티\mathrm{에이}N디$ = dissipation factor (Df)

RO4350B has Df = 0.0037 대. FR‑4’s 0.020. That reduces dielectric loss by about 80%, ensuring low‑loss transmission up to 30GHz.

Thermal‑mechanical stability: RO4350B’s Z‑axis CTE of 32 ppm/℃ matches copper (17 ppm/℃) far better than FR‑4 (50–70 ppm/℃). This improves plated through‑hole (PTH) reliability under thermal cycling. Tested per IPC‑TM‑650 2.6.7, the board survives 1000 cycles from -55℃ to 125℃ without delamination.

5. 기본 응용 프로그램

UGPCB’s 6‑layer communication high frequency hybrid PCB serves five major areas:

5.1 5G Communication Base Stations (AAU/RRU)

• Frequency bands: 28GHz and 39GHz millimeter wave
• 요구 사항: Insertion loss < 0.31 dB/cm@40GHz, power handling >200 W/m²@38GHz
• Advantage: Hybrid construction cuts material cost by 30–40% vs. all‑high‑frequency material

5.2 77GHz/79GHz Automotive Radar

• Use cases: Autonomous driving 4D imaging radar, blind spot detection, 적응 형 크루즈 컨트롤
• 요구 사항: Range error <0.25m from -40℃ to 125℃, azimuth resolution 0.08°
• 성능: IMS 2025 report shows phase consistency of ±0.8° over full temperature range for 77GHz hybrid radar modules

5.3 Satellite Communication Payloads (Ka‑band)

• Frequency range: 17.7 - 31 GHz
• Advantage: 45% weight reduction vs. ceramic substrates while maintaining >85% efficiency

5.4 Fiber‑to‑the‑Home (FTTH) 장비

• Market trend: Global IPTV market from $189.25B (2025) to $421.53B (2030), cagr 17.4%
• 영향: High‑bandwidth, low‑latency PCBs are essential

5.5 High‑Speed Digital Mixed‑Signal Systems

• Fields: Medical imaging, industrial high‑frequency inspection, military communication terminals
• 요구 사항: Coexist 10+ Gbps digital signals with GHz‑range RF signals

6. 과학적 분류 (per IPC‑2221)

Classification Dimension	범주	Basis
Material system	Mixed dielectric PCB	RO4350B + FR-4
Frequency characteristic	RF / 마이크로파 PCB	Up to 30GHz
레이어 수	6‑layer multilayer board	6 전도성 층
Technical difficulty	HDI hybrid lamination	Non‑expansion material matching
애플리케이션	Communication RF PCB	통신 인프라
IPC performance class	IPC‑6012 Class 3	High‑reliability equipment

7. Materials in Detail

7.1 RO4350B High‑Frequency Laminate

• Glass‑reinforced hydrocarbon + 세라믹 필러
• DK: 3.48±0.05@10GHz, temperature coefficient ~ -50 ppm/℃ (-50℃ to +150℃)
• Df: 0.0037@10GHz
• Z‑axis CTE: 32 ppm/℃ – matches copper for PTH reliability
• 열전도율: 0.69 w/m · k (대. FR‑4 0.25–0.35)
• UL 94 V‑0 – suitable for active and high‑power RF designs
• Process compatibility: Same FR‑4 processing; no special pre‑treatment needed (unlike PTFE)

7.2 FR‑4 Epoxy Glass Laminate

• Woven glass fabric + 에폭시 수지
• DK: 4.2–4.8 (1MHz–1GHz), Df: 0.020–0.025
• 비용: 1/5 에게 1/10 of RO4350B

7.3 RO4450™ High‑Frequency Bondply

• Bonding layer between RO4350B and FR‑4
• DK: 3.52±0.05@10GHz (gradient transition)
• Df: 0.0040@10GHz

7.4 ENIG Surface Finish (무전해 니켈 침지 금)

• 니켈 두께: 3-6μm (IPC‑4552 Class 2)
• 금 두께: 0.05–0.10μm
• 장점: 납땜 가능성, flatness, 내산화성, fine‑pitch BGA assembly
• 기준: IPC‑4552

8. 성능 사양

8.1 전기적 성능

매개 변수	값	테스트 방법
Characteristic impedance (RF layers)	50Ω ±5% (customizable)	IPC‑2141A
DK (RF layers @10GHz)	3.48± 0.05	IPC‑TM‑650 2.5.5.5
Insertion loss	0.31 dB/cm @40GHz	Microstrip line VNA
Dielectric strength	≥40 kV/mm	IPC‑TM‑650 2.5.6
단열성 저항	>10⁹ Ω (normal condition)	IPC‑TM‑650 2.5.17
Withstanding voltage	1000 VDC, 60s no breakdown	IPC‑TM‑650 2.5.7

8.2 기계적 성능

매개 변수	값	테스트 방법
Thickness tolerance	± 10%	IPC‑6012
치수 안정성	<0.3 mm/m	IPC‑TM‑650 2.2.4
박리강도 (1온스 구리)	≥1.0 N/mm	IPC‑TM‑650 2.4.8
Flexural strength	≥350 MPa	IPC‑TM‑650 2.4.4
Pad pull‑off force	≥5.0 kg/cm²	IPC‑TM‑650 2.4.21

8.3 열 성능

매개 변수	값	테스트 방법
Tg (FR‑4 area)	≥150℃ (TG150)	IPC‑TM‑650 2.4.25
Thermal stress	288℃, 10s × 5 사이클	IPC‑TM‑650 2.4.13
열 사이클링	-55℃ ↔ 125℃, 1000 사이클, 박리 없음	IPC‑TM‑650 2.6.7
Lead‑free reflow	260℃, 5 사이클	IPC/JEDEC J‑STD‑020
Moisture sensitivity level	MSL 1	IPC/JEDEC J‑STD‑020

8.4 Reliability Certifications

• IPC‑6012 Class 3 – high‑reliability equipment
• IPC‑6018B – qualification for high‑frequency (마이크로파) PCB
• UL 94 V‑0
• MIL‑PRF‑31032 - 1000 thermal cycles from -55℃ to 125℃

100% flying probe electrical test + AOI. End‑product meets IPC‑A‑600 Class 3.

9. 구조적 특징

Asymmetric 6‑layer hybrid build:

• L1‑L2 (RO4350B): RF front‑end (아빠, LNA, 필터) – signal integrity critical zone
• L3 (이행): Impedance matching and signal layer change – isolates RF from high‑speed digital
• L4‑L6 (FR-4): Power management, 디지털 제어, mechanical support – low‑cost conventional circuits

ENIG finish: Flat surface ensures consistent impedance control. Supports BGA, QFN, fine‑pitch packages. Gold layer protects copper and guarantees solderability after long storage.

정밀 드릴링 & PTH: Minimum mechanical hole diameter 0.25mm (HDI microvias down to 0.1mm available). Hole copper thickness ≥20μm (IPC 클래스 3). Plasma treatment with different gas mixtures for RO4350B and FR‑4 layers.

10. 제조 공정 흐름

18 key steps:

① IQC → ② Inner layer imaging (RF and digital separately) → ③ Brown oxide → ④ Pre‑lamination plasma activation → ⑤ Hybrid lay‑up → ⑥ High‑pressure lamination (dynamic pressure curve) → ⑦ X‑ray target drilling → ⑧ Mechanical drilling (0.25mm 분) → ⑨ Plasma desmear (dual cycle) → ⑩ Electroless copper → ⑪ Outer layer imaging → ⑫ Pattern plating (구리 + 주석) → ⑬ Outer layer etching (tin strip) → ⑭ AOI → ⑮ Solder mask → ⑯ ENIG → ⑰ Electrical test → ⑱ Final inspection/packaging

Critical process details:

• Pre‑lamination plasma (step 4): CF₄‑N₂‑O₂ for FR‑4; helium (He) RO4350B용
• Lamination curve (step 6): Dynamic pressure – FR‑4 cures first (~180℃), then pressure and temperature rise to >200℃ for RO4350B
• 교련 (step 8): Step feed and tool life management handle hardness difference
• desmear & PTH (steps 9‑10): Dual‑cycle process due to different chemical behaviors; hole copper ≥20μm

11. 경쟁 우위

Cost‑performance balance: All‑RO4350B 6‑layer material costs >$200/m². Hybrid uses RO4350B only on 25% of thickness →30‑40% material cost reduction.

신뢰할 수 있음: RO4350B Z‑axis CTE = 32 ppm/℃ matches copper (17 ppm/℃). Full FR‑4 has 50‑70 ppm/℃. Hybrid reduces PTH stress. Passes 1000 cycles -55℃ to 125℃ (IPC‑TM‑650 2.6.7).

치수 안정성: Low CTE reduces warpage, improves SMT yield.

Direction	RO4350B CTE	FR‑4 CTE (전형적인)
X‑axis	10 ppm/℃	14 ppm/℃
Y‑axis	12 ppm/℃	16 ppm/℃
Z‑axis	32 ppm/℃	50‑70 ppm/℃

Vs. full PTFE (예를 들어, 로저스 RT/듀로이드):

특징	RO4350B+FR‑4 hybrid	Full PTFE
Process compatibility	Standard FR‑4 line	Special equipment & treatment
PTH metallization	기준	Sodium naphthalene or plasma
치수 안정성	훌륭한 (glass reinforced)	가난한, flows
비용	30‑50% lower	높은

12. 요약 & Inquiry Guidance

UGPCB’s 6‑layer communication high frequency hybrid PCB is the ideal interconnect for RF/digital mixed signal systems. It serves 5G base stations, satellite Ka‑band payloads, 77GHz 자동차 레이더, and high‑speed digital applications. By placing RO4350B only on the critical RF layers, we achieve optimal performance at a significantly lower cost.

Key data recap:

✅ Dk = 3.48 ± 0.05 @10GHz (Rogers official)
✅ Df = 0.0037 @10GHz
✅ Z‑axis CTE = 32 ppm/℃ (matches copper)
✅ Insertion loss ≤ 0.31 dB/cm @40GHz (IPC‑6018B verified)
✅30‑40% material cost reduction 대. all‑high‑frequency material
✅ Passes 1000 thermal cycles -55℃ ↔ 125℃

Limited‑time prototyping offer

📩 Get your custom quote and technical proposal

UGPCB offers a 7‑working‑day quick‑turn service for 4‑ to 10‑layer hybrid PCBs. 우리는 제공합니다 free DFM analysis.

👉 Send your Gerber files and stackup design to our technical support email. We will reply with a technical assessment and precise quote within 4 시간.

UGPCB – Your trusted hybrid high‑frequency PCB manufacturer. From prototype to volume production, we deliver one‑stop 6‑layer mixed dielectric solutions to accelerate your 5G and millimeter‑wave radar products.

*Data sources: Rogers Corporation RO4350B™ Data Sheet, IPC‑6012D/6018B standards, IPC‑TM‑650 test methods, GSMA 2026 telecom outlook, IMS 2025 International Microwave Symposium technical report.*