RE: nRF51822 matching circuit KC certification Problem

Asbjørn — Thu, 22 Jan 2015 11:29:22 GMT

For the testing you are doing it is useful to look at the system in two different sections. So the normal matching network that we add to our documentation is or the radio output. In addition it is also common for customer to have components to tune the antenna. These two networks are connected but the matching network from the radio (L1, L2, L3, C3, C5, C4 and C6) matches the radios differential output 50 ohm single ended. The antenna matching tune the antenna input impedance into 50 Ohm. So to answer your questions. 1: Yes, this is the radio matching network and must be there as it tunes the radios differential output into a 50 Ohm single ended output. This 50 Ohm output is where you would connect you measurement cable (Intersection of L3 and C6). 2: Removing matching circuit is the antenna match they have in mind. So if you have added component for tuning the antenna, these should be removed and the antenna should be cut/removed so that all energy out of the radio enters the measurement cable. L1, L2, L3, C3, C5, C4 and C6 must be kept.

2-1: Keep L1, L2, L3, C3, C5, C4 and C6 and solder the measurement cable on at the intersection of L3 and C6. Remove antenna tuning components and antenna. 2-3: See above.