How do you bias a varactor diode?

using RFC , to eleminate the RF in the DC path , and also use decoupling capacitors

khouly

it can be done by taking care that a RF signal is superposed over a constant negative DC supply to take care that the diode is in reverse bias....

Using ADCH-80 , http://www.minicircuits.com

Through a simple resistor of 33K... 100K since the current through the varicap is very very small +/- 10uA !..