I use ADF4159 and ADF5901 to generate 24GHz signal, but it still can not lock. The structure and test result are attached below. The PFD frequency of ADF4159 is 100MHz, AUX of ADF5901 is 12GHz, the settings are attached below. I use the ADIsimPLL4.20 to design the second order or third order passive loop filter, and I tried so many times, but it is still not work. Could you give me some recommended values? Thank you very much.