Regarding nRF51822 RF Performance

[Nazmus Sakib]

Hi All.

I am doing a BLE based project using nRF51822. My project is a Proximity Application. Where my device need to talk with an iPhone where I need around 150 Feet (Line of Sight) of Proximity Range. I used in my design nRF58122 QFAA Package and the below RF Parts:

Fractus Chip Antenna FR05-S1-N-0-102: www.fractus.com/.../DS_FR05-S1-N-0-102.pdf

Johanson Balun 2450BM14A0002: www.johansontechnology.com/.../2450bm14a0002-matched-balun-for-nordic-nrf24l01nrf24l01.html

I know Balun BAL-NRF01D3. is the best choice but I am not able to select it due to soldering difficulties.

I found the Chip Antenna FR05-S1-N-0-102 efficiency is good, 72% so I chooses it.

I checked on the nRF Antenna Design guide. Here as I used a ready made Balun so I think there is no other necessary to tune the antenna network as Balun is doing it. Please advise if I am wrong.

I found there are many nRF51822 Modules in Market with long BLE range. Like RFduino Module range I found on web search around 500 Feet (Line of Sight). So I thought my project also can get at least 150 Feet. But unfortunately I am getting only around 3 Feet ...

I used the nRF51822 Internal LDO Schematic Model. I have attached the Schematic and PCB RF trace picture.

Please advise me how to improve the range in such condition to achieve 150 Feet.

Looking forward your suggestion.

Regards.

Schematic_RF.JPG

PCB_RF.JPG

[FormerMember]

Yes, the range is the same for the CEAA (WLCSP) and QFAA (QFN) package when the antenna is tuned.

[Nazmus Sakib]

Hi Kristin.

Thanks for all your feedback. I like to ask the same ques again with some more information about my next plan.

• In my current PCB I used QFAA Package and all discrete antenna components (no Balun). After tuning I achieved around 150 feet range, which is fine for my project.

• In my next PCB design I want to reduce the Board size hence, I chooses CEAA Package. For Antenna I'll use Balun BAL-NRF02D3. I'll add a PI Network for tuning.

You already mentioned on your earliest message, QFAA and CEAA RF performance is same. But now I am little bit concern about Discrete components (old Board) vs BAL-NRF02D3 (new Board).

So in my new PCB (CEAA + Balun) with proper Antenna Tuning will I get similar range performance as my old PCB (QFAA + Discrete)?

Thanks in advance.

Regards.

[FormerMember]

Yes, the range with CEAA + balun should be similar to QFAA + discrete. In order to obtain good range with CEAA + balun it is important that you follow the reference layout for CEAA + balun.

[bvrm]

STMicro's application note AN4111 states a capacitor at the feed line for high power mode (4 dBm) with the BAL-NRF01D3 and nRF51822 QFN.

Does it also apply for the BAL-NRF02D3 and nRF51822 WLCS?

[seopyoon]

Hello Kristin,

I have a question regarding balun and antenna. If I put balun, and have no antenna (leave the SE pin on BAL_NRF02D3 open) would it advertise at lease?? (with low sensitivity)