Distance between main and Diversified Antenna to maintain


I’m using Quectel EC25-V module for my IoT application, my SBC (Single boad computer) gets the data from Local Radios of RTU’s and relays the same to Cloud using the Quectel EC25-V, module.

The antennas used for main And Div are FPC antenna sticked inside the enclosure, where we have faced a major failure of EMI emmissions, so in order to avoid this, we no longer use this FPC antenna, and will go with External Antennas for the main and Div antenna.

The only thing have to confirm is the ideal distance for the antennas should be,the antenna specs as follows

Antenna Specs:

Rubbber duck Wideband antenna,
** gain:3dBi,


What is the Horizontal distance of seperation should be maintained between these antennas?


Dear Shiva,
Thanks for your inquiry in Quectel forum.
About the distance between antennas have no exact requirement. Generally speaking, the isolation between the antennas should be at least 10dB to avoid interference. The actual distance will be determined by the consulting results from antenna supplier and also depends on your board size and layout. Thanks!
By the way, you also can check the following document to design your antenna. Thanks!

Quectel_Antenna_Design_Note_V3.1.pdf (1.1 MB)

Thanks Kyson , for the information, going back, we have used earlier, the FPC antennas were in the distance between these were 5mm, can we go ahead and maintain 20mm distance considering the Cellular modem operates in LTE mode with the above specs.

can this be workeable?

Dear Shiva,
I think it is enough, but it still need to use the real test data to prove it. Thanks!