NRF51822 beacon weak signal with balun and chip antenna

[romeoordos]

I'm building home temperature sensor with custom pcb design. I'm using balun(2450BM14E0003) and chip antenna(2450AT42B100) from Johanson Technology. Beacon works and it transmits the signal, but it is very weak (~ -95dBm), it's maximum range is about 15-20cm. I have tried to resolder balun and antenna several times to be sure that connection of all components is ok. Even if I remove balun and antenna the signal remains the same strength. I'm attaching my schematics and pcb layout. Please tell me what I could did wrong? Thank you.

Trace width from MCU to balun is 0.2mm.

Trace width from balun to antenna is 0.3mm. Trace length from balun to antenna is 2.35mm.

[Hung Bui]

2450BM14E0003 should be OK with our nRF51822. But the grounding has to be improved. You should have more ground plane on both side. 

[romeoordos]

May absense of Pi network between antenna and balun cause the issue?

Should I make UBAL trace wider?

[Hung Bui]

Yes, you can try making the trace wider and add the PI network for tuning. But if you don't have equipment to tune that wouldn't help. Improve ground would really help.