Radiated Emission problem with ADuM5402

Hi guys ,

I am using  ADuM5402 digital isolators with integrated DC-DC converter. Switching frequency of internal converter is 180 MHZ. It creating problem in Radiated Emission test So i have changed my PCB layout as per recommendation in AN-0971 (Recommendations for Control of Radiated Emissions with isoPower Devices by Mark Cantrell) .

Test again in EMC lab and Still problem same but reduced some radiation dB level. Please suggest solution for RE test pass.

I also want to experiment with alternate part no of ADuM5402 with low switching frequency. but i am not able to found the part. please suggest the compatible alternate part with less switching frequency. 

Thank you in advance.