nRF905 antenna

RE: nRF905 antenna

Witek — Wed, 13 Jan 2016 10:22:56 GMT

Hi Håkon,

Sorry, I misunderstood you.

Not having any experience with tuning antennas, I need a little help.

Do I understand correctly that to tune the antenna I need to plug the network analyser into the input of the PI-network with the antenna connected and the rest of the circuit disconnected?

Would an antenna vector analyser suffice for this task?

Would you be able to suggest a good application note for this?

Thanks Witek

RE: nRF905 antenna

Witek — Tue, 12 Jan 2016 01:35:38 GMT

Hi Håkon,

Thanks for your suggestion.

I expected that a matching network is required. I was hoping to use the example circuit given in the datasheet and just make adjustments to the components used for a better match to the antenna, but to do that I need to know a process to follow.

I guess with nRF905 I need a differential to single ended conversion circuit, and then a matching network. Given that, which components in the example circuit should I replace with the PI-network.

I hope I am making sense.

I appreciate you efforts in helping me to come up with a solution.

Thanks Witek

RE: nRF905 antenna

Håkon Alseth — Tue, 22 Dec 2015 09:22:28 GMT

Hi Witek,

A quarter-wave antenna will be approx. 36 ohms (If you look at it in a theoretical approach) when it's tuned to the correct length, but has no antenna tuner components.

You'll need to add components to your PCB between the 50 ohm output from the nRF and the antenna, preferably a PI-network, and tune your antenna to 50 ohms @ 433MHz using a network analyzer.

Best regards, Håkon