Triple Step-Up Power Supply
To get to 0.5 A at 30 V you will essentially need a boost converter. If the current requirement can be dropped substantially (maybe 100 mA, maybe 10 mA, I'm not familiar with what's available at these voltages), you could consider a switched capacitor voltage converter.

If you need low noise, you will then most likely have to filter the output to achieve your noise requirement. 

The filtering problem will be easier if you choose a switching frequency far away from your rf operating frequency (and without harmonics interfering with your rf operating frequency).