QUESTION

Question

Hi!

Our PCB is small and long, to fit in a small tube (scientific long-term data logger for natural hazards, runs up to >10 years with one battery set, using 2G / LTE-M1, local communication is with BLE 5.0, system supports secure FOTA via BLE and 2G/LTE-M1. If anybody is interested: please let me know ;-)  ),

124mm long and 19.5 mm height. We are using a SARA-R412-Modem in Europe,

First Samples (on a much broader) PCB with "Lucida" worked excellent, but now for the small PCB: Which Antenna could be used?

Thanks for any suggestions!
Jo

Answer 1

Hi Jo,

For a PCB like yours then Inversa will be ideal as this can be placed rotated 90 degrees to fit with your design. Please check the Inversa datasheet for the position suitable for your PCBA (SR4L034)

Answer 2

Hi Jo,

What Chris is referring to is the vertical mounting of the Inversa (see slide 16 of the data sheet). The antenna will need to shift to one of the longer sides but should be placed in the upper right or left corner of the image in your original question submission. All four layers will need to be stitched together with through hole vias in the area left void of components to offer a significant volume of copper for the antenna currents to operate against.
What is the separation between the antenna and the first battery. It should be 20mm.

Best regards,

Geoff S.

Answer 3

Hi all!

Just to ask again: no possibility for an Embedded Antenna, pointing to the long side?

Thanks for any suggestions!

Jo

Comments

Hi Jo,

Yes, you can mount the antenna along the long edge of the PCB but it cannot be placed in the center of the PCB as your image implies. It must be placed along the edge of the PCB with the proper keep out areas cleared of all copper through all layers of the PCB and the remaining areas filled with copper.

If this in not clear please contact our sale representative to further assist you with your design as they can review your Gerber files and make more detailed suggestions one on one.

Best regards,

Geoff S.