1. Customer Profile

Client:  Anonymous
Industry: Fiber Optic Test & Measurement, High-Speed Data Transmission
Application: Next-gen 100G/400G+ optical transceivers, OTDR equipment, and 50GHz RF test modules.

FIS designs precision fiber optic tools, requiring ultra-low-loss PCBs to maintain signal integrity at millimeter-wave frequencies (up to 50GHz). Their challenges include:

• Insertion loss degrading high-speed signals (>40Gbps).
• Impedance mismatches causing reflection noise.
• Thermal expansion leading to microvia cracking in compact designs.
  
  

2. KKPCB’s Solution

(A) High-Frequency PCB Design

• Material: Rogers RO4835 (Dk=3.48, Df=0.0037 @ 50GHz) + Megtron 6 hybrid stackup.

Key Specifications:

• 50GHz RF layouts with 0.1dB/inch insertion loss.
• ±3% impedance control (100Ω differential pairs for SerDes lanes).
• Laser microvias (0.1mm) for dense BGA breakouts (e.g., QSFP-DD).

(B) Signal Integrity Optimization

• EMI Shielding: Buried capacitance layers + via fences for cross-talk isolation.
• Golden Finger Plating: 0.3μm ENEPIG for repeated connector mating cycles.

(C) Thermal Reliability

• 2W/mK Thermal Pads under RF ICs (e.g., DSPs, TIAs).
• HASL-Free Surface Finish to prevent CAF in humid conditions.

(D) DFM for High Yield

• Automated Optical Inspection (AOI) for 3mil microstrip alignment.
• TDR Testing to validate 50GHz propagation.

3. Results & Measured Performance

Parameter	Customer’s Old PCB	KKPCB’s Solution	Improvement
Insertion Loss (40GHz)	0.8dB/cm	0.25dB/cm	68% ↓
Return Loss (50GHz)	-12dB	-22dB	83% ↓
Thermal Cycling	200 cycles	500 cycles	150% ↑
Time-to-Market	8 weeks	3 weeks	62% ↓

Validated in FIS Labs: KKPCB’s transceiver PCB reduced BER (Bit Error Rate) by 10^-12 in 400G DR4 modules.

4. Why FIS Chose KKPCB?

✔ Proven 50GHz RF Expertise: Lab reports with VNA/S-parameter data (attached).
✔ Fast NPI Support: 10-day prototype turnaround (vs. industry avg. 4 weeks).
✔ Cost-Effective Hybrid Stackups: Rogers + Megtron 6 savings ($200/panel vs. full Rogers).

5. Technical Highlights (Visual Storytelling)

(A) Stackup Cross-Section

Layer 1: Rogers RO4835 (Signal)  
Layer 2: Megtron 6 (Ground Plane)  
Layer 3-6: Mixed RF/Digital Routing  
Layer 7: Thermal Cu Flood (5oz)  
Layer 8: Aluminum Base (Heat Sink)

Figure: Hybrid material stack for optimized cost/performance.

(B) 50GHz Eye Diagram
Tested with Keysight Infiniium VNA (0.1UI jitter).

6. Call to Action

For Your Next Optical Transceiver Project:
➔ Submit Gerbers for a Free Signal Integrity Review 
➔ Request a 50GHz Test Report
Email: [email protected]
KKPCB – Your Partner in High-Speed RF/FO PCBs.