The question was more with regards to the higher order LO harmonic levels that are generated from the internal PLL synthesizer.
As per the data sheet the third order harmonic distortions are around @-30 dBc @1.4GHz and 2.4GHz @ 0 dB attenuation. But we observed third order harmonics in the final out put is around -14dBc @1.4GHz and -21 dBC @ 2.4GHz @ 0 dB attenuation in the evaluation board of AD9364. If This high harmonic levels of Tx / Rx LO is provided to an internal IQ Modulator/ Demodulator , then the performance of the IQ modulator and demodulator is degraded due to Phase imbalance and amplitude imbalance. why i am getting worst third order harmonics in my out put . please let me know to to improve odd order harmonics in the LO out put.