Custom design 4-Layer Hybrid High-Frequency DK3.3 PCB – WL-CT330 + High-Tg FR-4 (S1000-2M) substrate

4-Layer Hybrid High-Frequency PCB – WL-CT330 + FR4 (Immersion Gold)

Product Introduction

We present our 4-Layer WL-CT330 PCB with Immersion Gold – a hybrid solution engineered for high-frequency, high-reliability applications. The design combines a WL-CT330 high-frequency laminate (top two layers) with a High-Tg FR-4 (S1000-2M) substrate (bottom layers). This hybrid stackup delivers ultra-low loss RF performance on the outer layers while maintaining mechanical rigidity and cost-efficiency for the overall board. The 2.7mm finished thickness and 1oz copper on all layers ensure excellent power handling and thermal management.

Key Specifications

PCB Stackup (4-Layer Rigid Hybrid)

Note: No blind vias – all interconnections are through-hole vias, simplifying manufacturing and reducing cost.

PCB Statistics

Dimensions: 165 mm × 96.5 mm (1 piece)

Components: 45

Total Pads: 225 (126 thru-hole, 59 SMT top, 40 SMT bottom)

Vias: 63 (No blind vias)

Nets: 9

Why WL-CT330?

WL-CT330 is a thermosetting hydrocarbon/ceramic composite with fiberglass reinforcement. Unlike PTFE-based materials, it processes like standard FR4 (no special handling), supports lead-free assembly at 260°C, and offers a high Tg >280°C for exceptional thermal reliability. With a stable Dk of 3.30 ±0.06 and Df of 0.0026 at 10 GHz, it delivers consistent RF performance across temperature and frequency.

Key Features of WL-CT330

Dielectric Constant (Dk): 3.30 ±0.06 @ 10 GHz

Dissipation Factor (Df): 0.0026 @ 10 GHz

Tg: >280°C

Thermal Conductivity: 0.59 W/m·K

Thermal Resistance: T260 >60 min, T288 >20 min

Peel Strength (1oz ED copper): ≥0.85 N/mm

CTE (X/Y/Z): 15 / 13 / 39 ppm/°C

Moisture Absorption: ≤0.05%

Flammability Rating: UL 94-V0

Volume/Surface Resistivity: 5×10⁹ Mohm·cm / Mohm

Stable TcDk (temperature coefficient of Dk)

Benefits of This Hybrid Design

Cost-Effective: Only the RF-critical layers use high-frequency WL-CT330; the rest uses standard high-Tg FR4.

Process-Friendly: No PTFE-specific handling – compatible with standard FR4 fabrication and lead-free assembly.

Thermally Reliable: High Tg (>280°C) and low Z-axis CTE reduce risk of via cracking during reflow.

Signal Integrity: Ultra-low Df (0.0026) minimizes insertion loss for high-speed digital and RF traces.

Immersion Gold Finish: Provides a flat, solderable, corrosion-resistant surface for fine-pitch SMT components.

Typical Applications

5G/6G Infrastructure: Base stations, phased array antennas

Automotive Radar: ADAS, V2X communication modules

Satellite Communications: Navigation, ground terminals

Aerospace & Defense: Early warning radar, airborne systems

RF Power Amplifiers & Transceivers

High-Speed Backplanes: Servers, networking switches, data center equipment

Quality Assurance

100% electrical testing prior to shipment

IPC-Class-2 compliance

Full Gerber RS-274-X acceptance

ISO 9001 certified production

Ordering Information

Submit your Gerber files and fabrication drawings. We support prototype to volume production with global shipping. Contact us for lead times and pricing based on your annual consumption.