Basing my design on PCA10028. Do I need to include both C6 and C15

[mosi]

I'm basing my schematic and antenna design using the PCA10028 as a reference.

I'm not including the J1 RF-connector into my design. Do I still need to include both C6 and C15?

In the nRF51822 Product Specification there is only one 1.5pF capacitor just before the antenna.

[Øyvind Karlsen]

Hi,

Have a look at the general PCB design guidelines for nRF51. C15 is part of the antenna circuit, the antenna structure is matched to 50 Ohms using a PI network. In the case of a quarter wave printed monopole the PI network can be simplified by shortening the antenna until it reaches the desired impedance (G=1 circle in the smith chart), then removing the inductance by adding a shunt capacitor, seen by C15 on PCA10028.

C6 is part of the output match for the nRF51822 and must be included.

Best regards,

Øyvind