Support needed for the RF test failures above 1 GHz for the EC20 module and advise what technical or configuration changes are needed to pass CE certification

IoT Modules LTE Standard Module
1

Hello team,

Our device Fasal 5.0 is currently under testing for MTCTE compliance as well as CE standard reports. During wireless/RF testing above 1GHz for Fasal 5.0
(Module: EC20CEFILG-128-SGNS ,Modem Firmware: EC20CEFILGR08A03M1G), we observed multiple failures, as shown in the attached image.

I understand that Quectel team has already mentioned that the EC20 is only for the India and China market, so the CE certification was not carried out. However, as we are expanding our business into new regions, CE certification for our device has now become a critical requirement to our international deployments and market entry.

Kindly go through the attached graph and let us know what actions can be taken in order to successfully complete the CE testing for 5.0 (EC20) without any failures.
At this stage, this issue is the only major blocker preventing the completion of Fasal 5.0 compliance.
Let us know if you need any additional information.

Thanks,
Shashank

EC20_module_testing_above_1GHz_failure
EC20_module_testing_above_1GHz_failure1115×713 74.2 KB

2

Dear Customer,

Unfortunately, the EC20CE is intended only for the India and China markets and is not CE certified. The most suitable approach would be to migrate to the EC25. However, if design constraints or cost considerations are a concern, we can propose several alternative options.

If you need to continue using the EC20 module, CE compliance may still be achievable through system-level RF mitigation. Typical actions include adding or optimizing an RF low pass / harmonic filter on the LTE TX path to suppress higher order harmonics, improving RF layout and grounding on the antenna feed, and enhancing shielding and isolation to reduce radiated coupling. Power integrity should also be reviewed, especially VBAT noise during TX bursts, and antenna matching should be reverified to ensure a good 50 Ohm match. As a temporary workaround, reducing TX power may help, though this may impact coverage and product performance.

To provide more targeted recommendations, please confirm whether the failure is conducted or radiated spurious, the detailed test conditions (band, channel, TX power, RBW/VBW, test mode), and whether the issue is consistent across multiple units or limited to specific samples.

Best Regards,
Fazrul Redzuan

3

Hello Fazrul Redzuan,

Thanks for sharing your prompt response.
We have finalized the hardware design and the product is already in production. In parallel, we are progressing with our TEC and RED-CE certification activities. At this stage, migrating to EC25 or implementing hardware modifications (such as adding a low-pass or harmonic filter) would not be feasible.

The testing was conducted in a 3-meter semi-anechoic chamber using the radiated method .
As shown in the attached image, the failure was observed under the following conditions:

  • Band: 3
  • Channel: 1784.2 MHz
  • Channel Bandwidth: 1.4 MHz
  • Resource Allocation: Only 1 Resource Block , positioned at index 0
  • Antenna Orientation: Horizontal
  • Test Method: Radiated

Please note that the above test result is limited to one specific unit , and we have not yet repeated the test across multiple samples.

The visible failures are at approximately 1.78 GHz, 3.56 GHz, and 5.36 GHz . Could you please confirm whether these correspond to internal frequencies or harmonics of the 4G modem?

Kindly advise if there are any possible mitigation approaches that could help reduce these failures and enable us to successfully close this open point.

Thanks,
Shashank

EC20_module_testing_above_1GHz_failure
EC20_module_testing_above_1GHz_failure1115×713 74.2 KB

4

Dear Customer,

Apologize for late response since we were having public holiday for past 2 days.

For the suggestion, perhaps you can try as below actions:

  • Retest with 3–5 units (same chamber setup).
  • Rotate/shift the antenna a few millimeters. Repeat H/V sweeps.
  • Add one small absorber patch inside near the antenna feed or suspected seam, resweep.
  • Clip on ferrite to the antenna coax (if accessible).
  • Redress internal cables, ensure all screws fully tightened.
  • If allowed, 1–2 dB TX back‑off and reverify.

Regards,
Fazrul Redzuan

5

Dear Fazrul Redzuan,

Kindly find the answers for your suggestions below:

  • Retest with 3–5 units (same chamber setup). - As you are aware, compliance and pre-compliance testing are high-cost activities and cannot be easily repeated . Additionally, securing test slot availability is also challenging. So, multiple retest is not an option.
  • Rotate/shift the antenna a few millimeters. Repeat H/V sweeps. - The device under test is placed on a rotating table, and the readings are recorded at multiple heights.
  • Add one small absorber patch inside near the antenna feed or suspected seam, resweep. - Have not tried this yet.
  • Clip on ferrite to the antenna coax (if accessible). - Technician replied that ferrite can either suppress or increase the failure. And it is not a suitable solution to our device.
  • Redress internal cables, ensure all screws fully tightened. - I can assure you that all the internal cables follow single path and each and every screw is tightened by a torque gun only.
  • If allowed, 1–2 dB TX back‑off and reverify. - Please can you explain me this point?

Additionally, as EC20 is compliant for India and China. Are there any test reports or certification reports/graphs for reference. Even our partner lab is interested to have a look at these test reports/graphs.

Thanks,
Shashank

6

Dear Customer,

I will send to you through email.

Regards,
Fazrul Redzuan