Failing an EMC test on the first attempt is one of the most common experiences for R&D and QC teams — don't panic, most issues have well-established fixes.
Radiated Emissions Exceeding Limits
This is the most common failure, usually related to PCB layout, clock circuits, or grounding design. Common fixes include:
- Optimizing PCB traces, shortening high-frequency signal line lengths
- Adding shielding enclosures or shielding materials
- Adjusting grounding to ensure sufficiently low ground impedance
- Adding ferrite beads on critical signal lines
Conducted Emissions Exceeding Limits
This most often shows up at the power input. Common fixes include:
- Adding an EMI filter
- Optimizing power module layout to reduce switching noise coupling
- Checking whether cable shielding is properly grounded
Immunity Test Failures
The product exhibits abnormal behavior (crashing, resetting) under external electromagnetic interference. Common fixes include:
- Adding decoupling capacitors to critical circuits
- Optimizing the software watchdog mechanism for automatic recovery after abnormal events
- Adding common-mode chokes on signal lines
Recommended Remediation Process
- Get the detailed failure data (not just "failed" — look at the specific frequency band and how much it exceeds the limit)
- Have your engineering team assess whether a hardware or software-level fix is more cost-effective
- Validate the fix on a small batch of samples
- Retest to confirm
Throughout testing, we provide detailed raw data and engineering recommendations — not just a pass/fail conclusion — so your team can pinpoint issues more precisely and reduce the number of retest cycles.