QUESTION

Question

Hello all,

We are looking for a dipole antenna since in our application, a 1/4 wave whip antenna has not sufficient performance.

We have ordered the part with typenumber: SREI038-IPP at Mouser and we will evaluate and test this antenna.

The issue I have is that the antenna is not omndirectional as per datasheet as that is probably an issue,

but we will test the performance in our application.

As reference we have tested with the RHD-771 (SMA-M) 1/2 lambda omnidirectional dipole from Retevis (37cm) and

with this antenna the performance is correct:

https://www.retevis.com/sma-m-elite-antenna-u-v-antenna-for-retevis-rt1-rt2-rt3.

The problem is that we need an antenna  with about 1/4 lambda (or smaller) to fit in our application.

Also we do not have room adding a groundplate at the base of the antenna.

Please let us know your further recomendations / possible alternate solutions.

Thanks and regards,

Marcel Krisman.

Answer 1

Hello Marcel,

I know I followed up via email but would like to address your question here as well so others with similar concerns may benefit.

When electrically shrinking an antenna from 1/2 wave to 1/4 wave or smaller, you are sometimes sacrificing some of the patterns omni-directional qualities in order to satisfy ID or product implementation. This is especially true as you go lower into the 433MHz (and lower) ISM frequency bands.
Without knowing the specific application for each end product, we create antennas that work for the majority of applications by ensuring they're highly efficient, devoid of major nulls, and (in the case of the SREI038 433MHz external dipole) available in multiple terminal options to ensure flexibility in deployment.
We will follow-up via email to discuss your application and make the proper recommendations.

Thank you,

Dan Dobransky