Hello,
I've created a board for 868MHz communication, and matched its pcb antenna with a VNA. Note that measurements were taken from a micro-connector connected to the transmission line, not at the transmission line itself.
According to my measurements, I have achieved a good match (appx 1.3:1) at the target frequency. When measuring RSSI, it _looks_ like I am receiving pretty decently. But looking at noise floor, I am roughly 15 dBm worse than another antenna (connected to the same connector as I used to measure my pcb antenna).
The question I have is: can a poorly matched antenna produce the observed high noise floor? Or could this be a factor of the pcb antenna itself?