Hi All,
I have been developing a bluetooth chip based on nRF51822 QFAC. I have followed the design rules very closely but at the end I do not get any bluetooth signal coming from the Johanson antenna (2450AT18A100). I use the balun Johanson 2450bm14e0003. I have tried to follow the design given at www.johansontechnology.com/nordic . For the transmission line I have determined the track width using an online impedance calculator. I am using a 4-layer board and the distance from the top layer to the inner ground plane is 0.2mm ~ 7.8 mil. With this specification the 50 ohm trace width is calculated to be 13.6mils.
To test the device I have flashed the soft device S110 v8 and the example application "UART over BLE".
The photo of the layout and the assembled pcb board are attached. Note that, initially I have just used 0 ohm resistance for L1 and then tried several shunt and serial inductor and capacitor combinations with no luck. Even there would be some mismatch I would expect the iPhone to detect the device in the very close proximity. Appreciate your help. Thanks.
