I have a custom PCB with nRF51822. I have copied the "QFAA QFN48 with internal LDO setup" schematic from Product Specification v3.1. However, I have not copied the PCB layout. The radio is working, but probably not very well. (I use a PCB antenna).
I'm new to antenna applications. How would I go about measuring the antenna performance? What equipment do I need? Seriously, I need a step-by-step guide.
I have read the Antenna tuning white paper (nWP-017) and I understand it in theory (engineering school was good for something). The examples at the end are good, but going from reading it and understanding to actually doing it is a big step. I have no idea where I would start. It talks about adjusting the length of the antenna, but how do I do this? Do I use a knife to scrape some of my PCB antenna off???
And about the shunt capacitor. Would I simply have some different capacitors available, and try and solder one of them, do the measurements, solder another one and do the measurements again, until I find the right value?
Do you think I should redo my antenna PCB layout to exactly match the reference layout (matching network to chip)? A quick price comparison of the matching network components vs. Johanson Technology Balun showed that the balun is cheaper? Have I made a miscalculation? If the balun in cheaper, why would I not choose the balun? Is there some advantage in having the matching network over the balun? The balun seems simpler... Is it?
I guess this is the pain of transferring from school to real life...
