ble antenna report

[astella]

To the kind attention of Nordic support team,

We noticed that our BLE antenna reports we receive from our provider are somehow cumbersome and difficult to read, containing non standard non relevant info, or info that are not always the same, or info that are not always in the same order or presented in different ways. So we want to propose a report template, that would always be the same, containing info always in the same order and in the same way so to be clean and handy for understanding and comparison. After analyzing multiple BLE antenna datasheets this template seems would do. As we would like to work on this template and complete it, could you please tell me based on your experience if there is anything else you would change/modify, add/remove? It is just a very first quick template, just to start. And the idea is to have the complete characterization of the radio system, antenna tuning as well as radio tuning. As for different PCBs, it is better to give a look at the mcu matching network. Please feel free if you want to add values for different parameters you consider a good acceptable result in desktop environment.

 For example some data I found about desktop environment and mifa:

1. BLE applications such as wireless mouse requires an RF range of only about 10 feet and data rate of a few kbs (range is implicit in following antenna project: dimensions, pcb stack, etc)
2. mifa is considered the pcb antenna that requires minimum area about 7.2 mm * 11.1 mm (for wireless mouse)
3. return loss > 10dB (s11 < -10dB)
4. bandwidth 230MHz around 2.44GHz (10% reflection in the and 0.6% reflection at 2.44GHz) (more bandwidth helps in case of detuning)
5. radiation pattern (to choose the best placement)
6. gain 1.6dBi
7. antenna tuning and radio tuning first on bare PCB
8. enclosure and ground detune the antenna as well as human body contact, final antenna tuning and radio tuning

About radiation patterns, what would be in your opinion the best 2D representation? The azimuth and elevation plane patterns are usually ok? Because there is someone providing other cuts 

(YZ Vertical / YZ Horizontal - XZ Vertical / XZ Horizontal - XY Vertical / XY Horizontal). 

an_ble.pdf

Best regards

[ketiljo]

I guess this is too dependent on the specific design and hard to generalize like this. Things like size of the ground plane will have great impact on the antenna performance. So for small designs, you really need to look into the actual design. It's not easy / impossible to compare two different designs. 

[astella]

Hi ketiljo, thank you. I understand your point of view about general considerations about performance. Nevertheless, let us focus about measurements, you think a report like that would be a good starting point? You would add any other particular measurement/test that would be relevant, based on your experience? Thank you

[ketiljo]

For any product, the only important parameter is range. If you have optimized the antenna as best as you can, and the range is what you require, you should be good. If the range isn't what's required, you need to do something with the overall antenna design. Radiated antenna measurements on the actual design is what matters. Paper numbers, like gain, impedance and radiation pattern doesn't matter much as it will probably be different on your design. 

[astella]

Hi ketiljo thank you for underlining again the importance of the only real goal to achieve. I really appreciated your answer, as I was risking losing myself in fruitless speculations. Best regards