Bluetooth antenna on a narrow PCB
you can use the Johanson 2450AT43A100 without the 50ohm feed line to reduce space and mount is as close as possible ti the output pin of the BT SoC. Because you are using a ground plane which is longer than a quarter wave length the only difference if you use a less wide ground plane is that the radiation polar diagram will be more of a donut shape this means that the antenna will have significantly higher gain on the sides than on the top/bottom. Please note that by referring to "the the Antenna" i mean the whole set including the ground plane. The antenna will behave as half wave dipole.