how can i use varactor diode in ads for a microstrip bpf

[saeed3406]

i wanna simulate a microstrip tunable bpf in ADS and i dont know how to find and use the varactor diode
please help me

 

[biff44]

a capacitor with a resistor in parallel is a good start. And don't forget to include any package parasitic reactances too

 

[saeed3406]

thanks for your advice
but i need a varicap element and i cant find it in ADS.
do you have any idea where could i find that?