NRF24L01 basic trace antenna, load cap tuning and lenght

[patallen]

i get various answer about this, been in the rf design for a while, we used to make global antenna lenght on some give am ook circuit a tad shorter and then use a load cap to fine tune to get maximum performance (ie range and sensitivity)

is it valid for the NRF24L01+ at 2.4ghz ?

righ now its a mock up pcb and i did test it, it works but i get low range (ie about 30ft)

antenna trace highligthed in white is single ended connection left open at the end, and is exactly 3.125 cm, width is 0,7mm.

C6 load cap is 1pf per design guide from the data sheet.

thanks for any advice to improve range.

[mathiaso]

Hi, Patrick.

The easiest way to tune a trace antenna is to give some extra length at first and then cut it to have it resonate at the desired frequency. A shunt component might often be helpful to bring its impedance closer to 50 ohms. We do have this white paper on PCB trace antenna design that you might find helpful.

To be able to tune the antenna in a good way, you'll need to connect it to a VNA. I don't know if this is something you've got access to? We have this white paper on antenna tuning as well.

Best regards,
Mathias

[patallen]

document is very interesting and is a good start point. i do have a vna but cannot reach 2.4ghz... how about a 1/2 wavelenght antenna of the same manner ? thanks.

[mathiaso]

As you likely have some extra length on your antenna now, and you have limited equipment available, I'd suggest that you try tuning your antenna by trimming 1 mm off it at a time, until you reach a maximum range.