ive got some miscalculations as with regards to the impedance at
2.4ghz..
thanks.

i need more negative bias because the pin diode im using maximum Vr is
in -50V. reversing it with higher voltage will increase its isolation
capability as compared to a logic 0 volt level.

With reverse bias, the PIN diode looks like a capacitance. Resonate
that capacitance with a parallel inductor, and you'll do more for
isolation than you will by increasing the reverse bias from 5V to 40V.
I assume you're not dealing with signals that are several volts in
amplitude...