how to select a toroid

i am designing a SPDT pin diode based switch in the frequency band of 30-500MHz. i need RF chokes to provide bias to diodes and to isolate RF energy entering into the DC bias. all my ports are 50Ω . so i need minimum impedance of choke is 200Ω. my biasing currents are 100mA.
so please suggest me a suitable toroid material.