asked by
Calvus spacing from GND plane

Hello, I'm using Calvus in a 2G application (900/1800). I have placed the antenna in a space saving configuration, as mentioned in the datasheet, but I don't know what is the exact clearance between antenna pads and gnd copper (A), could you clarify?

Also, I would like to know if there is any impact in the performance with the main feed trace not being straight (B). 


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1 Answer

answered by
Hi Reinoso,

The Calvus was design to run perpendicular to the ground plane like a monopole antenna. Running the antenna parallel to the ground plan will cause the antenna fields to shunt to ground and not radiate as well as having the antenna trace on the antenna become detuned off the primary bands of resonance running it next to ground.

I would suggest using the Integra instead and slide it all the way to the bottom of your antenna area in order to run as much ground next to the top area of the antenna where the antenna feed trace is routed. You will also need to clear away some additional ground toward the bottom of the antenna area to comply with the antenna keep out area listed on page 13 of the data sheet.

Best regards,

Geoff S.
commented by

Hi Geoff, 

So, I cannot use A10340H in this parallel configuration even if I only need two bands (900/1800)? 

PS. My ground plane is only 52 mm long 


commented by
Hi Reinoso,

We cannot say whether it would work or not in that configuration with the reduced band requirements you mentioned. My concern would also be the shortened length of your ground plane. Calvus works best with 85mm of copper ground length below the short edge of the antenna. 52mm is significantly shorter so if it was place perpendicular to the ground plane your antenna efficiency would be reduced by at least 30%. Since it is parallel to a short ground plane I can't say that it would achieve the desired performance you would need unless you are working with a reduced range requirement. The only way to tell whether or not your configuration will work would be to send us your board with our antenna mounted and we can take a look at the performance.
You can contact to arrange sending a unit to us.
commented by
Hi, we have finally decided to change our design and use Integra as you suggested. Also our board shape, increasing the total length to 75mm (just like the SR4L049-EVB-3). Will contact by mail in a few days in order to get further support.

commented by
Sounds great! I look forward to helping you in the future!!

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