ADF4371 VCO and 3 X VCO suppression at Doubler output


In ADF4371 datasheet doubler output section mentioned that "the VCO and 3 × VCOfrequencies are suppressed regardless of the output frequency.
Suppression of <50 dB is typical".

But in 11.45 GHz - 13.66 GHz band, both manual(as per table 6) and automatic tracking, only 3 × VCO frequencies are suppressed to <50 dB and we get <25 dB suppression for VCO frequencies.

Any suggestion for  <50 dB suppression of VCO frequencies in doubler output?

[edited by: Karthi R at 10:26 AM (GMT -5) on 24 Dec 2020]