Signal Integrity in Board-to-Board Connectors: Why It Matters for 5G Infrastructure

📅 March 31, 2026 | 📂 High-Speed Connectors | 👤 Richmon

When your 5G equipment drops data packets or shows signal errors, the problem might not be in your chips or software. It could be in your connectors. Board-to-board connectors carry signals between PCBs, and if they don’t maintain signal integrity, your entire system can fail.

For OEM and EMS procurement teams working on 5G projects, understanding signal integrity in connectors is no longer optional. It’s essential for making the right sourcing decisions.

What Is Signal Integrity in Board-to-Board Connectors?

Signal integrity refers to the quality of an electrical signal as it travels through a connector. In board-to-board connectors, this means the signal arrives at its destination without distortion, noise, or timing errors.

In 5G applications, data moves faster and at higher frequencies than ever before. Signal integrity becomes critical because even small losses or distortions can cause data errors, slower performance, or complete system failure.

Term	What It Means
Signal Integrity	The quality of a signal as it passes through a connector
Impedance	Resistance to signal flow, measured in ohms (Ω)
Insertion Loss	Signal strength lost as it passes through the connector
Return Loss	Signal reflected back due to impedance mismatch
Crosstalk	Interference between adjacent signal lines

Why Signal Integrity Matters for 5G Infrastructure

5G networks operate at much higher frequencies than 4G. While 4G typically operates below 3 GHz, 5G can operate at frequencies up to 39 GHz in some bands. At these frequencies, every connection point becomes a potential source of signal degradation.

Poor signal integrity in connectors can lead to:

• Data errors: Corrupted signals cause wrong data transmission
• Reduced throughput: The system must retransmit failed data packets
• System instability: Intermittent connections cause unpredictable behavior
• Failed certifications: Equipment may not pass regulatory testing
• Increased costs: Rework, delays, and warranty claims add expense

For procurement teams, this means connector selection directly affects product reliability and total cost of ownership.

The Cost of Getting It Wrong

When signal integrity issues appear after production has started, the consequences are expensive:

• Redesign cycles cost time and money
• Field failures damage brand reputation
• Warranty claims increase support costs
• Delayed launches hurt competitive position

Choosing connectors with proper signal integrity specs from the start avoids these problems.

Key Specifications That Affect Signal Integrity

When evaluating board-to-board connectors for 5G applications, focus on these specifications:

1. Frequency Rating and Bandwidth

Connectors have a maximum frequency they can handle. For 5G applications, you need connectors rated for the highest frequency in your system. Using a connector beyond its rated frequency causes signal degradation.

Check the datasheet for frequency bandwidth specifications and verify they match your application requirements.

2. Impedance Control

Impedance matching is critical for high-speed signals. Most high-speed systems use 100Ω differential pairs or 50Ω single-ended signals. If the connector impedance doesn’t match the PCB design, signal reflections occur.

Signal Type	Standard Impedance	Why It Matters
Single-ended	50Ω	Matches most RF and high-speed standards
Differential pair	100Ω	Standard for high-speed data (PCIe, USB, etc.)

3. Insertion Loss

Insertion loss measures how much signal strength is lost through the connector. Lower values are better. For 5G applications, insertion loss should be minimal across the frequency range of operation.

Ask suppliers for insertion loss graphs showing performance across frequencies.

4. Crosstalk Performance

Crosstalk occurs when signals on one line interfere with adjacent lines. High crosstalk can cause data errors and signal integrity problems, especially in dense connector configurations.

Look for connectors with:

• Low crosstalk specifications
• Proper pin-to-pin spacing
• Ground shielding between signal pairs

5. Shielding Effectiveness

Shielding protects signals from external electromagnetic interference (EMI) and prevents the connector from emitting interference. For 5G applications, proper shielding is essential.

Good shielding includes:

• Metal shields around signal contacts
• Proper grounding to the PCB
• Shield walls between signal rows

How to Evaluate Signal Integrity in Connectors

When sourcing board-to-board connectors for 5G applications, use this evaluation approach:

Step 1: Define Your Requirements

Start by documenting your signal integrity needs:

• Maximum operating frequency
• Required bandwidth
• Allowable insertion loss
• Acceptable crosstalk levels
• Impedance requirements (50Ω or 100Ω)

Step 2: Request Technical Data

Ask suppliers for:

• S-parameter data (S11, S21, etc.) for simulation
• Insertion loss and return loss graphs
• Crosstalk specifications
• Frequency bandwidth ratings
• Impedance control specifications

Suppliers who can provide this data demonstrate capability in signal integrity performance.

Step 3: Compare Specifications

Create a comparison table for your connector options. Include all key signal integrity parameters and verify that each connector meets your minimum requirements.

Step 4: Check for Second Sources

For production reliability, verify that multiple suppliers can provide connectors with equivalent signal integrity performance. This reduces supply risk.

Common Mistakes to Avoid

When sourcing connectors for 5G infrastructure, avoid these errors:

Mistake	Consequence	How to Avoid
Selecting based on price only	Signal degradation, system failures	Evaluate signal integrity specs first
Ignoring frequency ratings	Poor performance at high speeds	Match frequency rating to application needs
Not requesting S-parameter data	No simulation support, design risks	Ask for S-parameters during sourcing
Assuming impedance control	Reflections and data errors	Verify impedance specs in datasheet
Overlooking second source	Supply risk, production delays	Check for multiple suppliers upfront

Practical Checklist for Sourcing Teams

Use this checklist when evaluating board-to-board connectors for 5G applications:

Signal Integrity Requirements

• What signal speed and frequency range do I need?
• What is the maximum insertion loss my system can handle?
• Do I need 50Ω or 100Ω impedance?
• What crosstalk level is acceptable?
• What shielding level do I need?

Supplier Evaluation

• Can the supplier provide S-parameters for simulation?
• Are insertion loss and return loss graphs available?
• Does the connector have proper signal integrity documentation?
• Can the supplier support technical questions about signal performance?

Supply Chain Considerations

• How many mating cycles are rated?
• What are the environmental ratings (temperature, humidity)?
• Is there a second source available?
• What is the lead time?

Quality and Traceability

• Does the supplier provide test data or compliance reports?
• Can the supplier provide Certificate of Conformance (CoC)?
• Are the connectors traceable to the manufacturer?

Conclusion

Signal integrity in board-to-board connectors directly affects 5G infrastructure performance. For OEM and EMS procurement teams, understanding these specifications is essential for making informed sourcing decisions.

When evaluating connectors, focus on frequency rating, impedance control, insertion loss, crosstalk, and shielding. Request S-parameter data and compare specifications across suppliers. Always verify second source availability to reduce supply risk.

By selecting connectors with proper signal integrity performance, you avoid costly redesigns, field failures, and production delays. Your sourcing decisions today affect your product’s reliability tomorrow.