asked by
Reference circuit for EMC compliance
Dear Sir/Madame,

In a project where I'm using your model SR4L002 (Lucida) connected to a GPRS module (Quectel M95), I sent the PCB designed by me for the CE-RED and FCC certifications to a lab and all tests passed except RF Radiated Emissions which fails due to GPRS harmonics.

Analizing the circuit I realised that for the Inductor connected into pin 4 of the Lucida Antenna, by mistake, I mounted a 2.2nH inductor instead of the recommended value (15nH).

My question is if, from your point of view, you think that an unbalanced value in that inductor could be noisy enough to fail radiated emissions test (the test restriction is the lowest one as it's a general consumer product).

Thank you very much in advance

Please log in or register to answer this question.

1 Answer

answered by
Yes, it can fail due to the self resonant frequencies of the two components. The 15nH will tend to block unwanted harmonics whereas the 2.2nH will allow the harmonics to go from the PCB ground through the antenna and into the radio front end to be re-radiated.
commented by
Thank you very much for the answer. It's been very useful.
Best wishes.

Meet the moderators

Nansen Tsai

Engineering Manager Nansen has a wealth of technical RF and wireless knowledge, with particular expertise in RF development and problem-solving.

Geoff Schulteis

Senior Antenna Apps Specialist at Antenova Geoff is an antenna design-in and OTA measurement specialist. His knowledge of FCC and world carrier requirements is second-to-none.

Steve Bradburn

Senior Antenna Engineer at Antenova With over 25 years’ experience in manufacturing, test and design, Steve has a wealth of RF and measurement knowledge across many industry sectors.


Antennas: The Comparison Guide

Find the perfect antenna for your project