Tuning range when varactor is placed parallel to a capacitor

[redhat]

after putting a varactor to an LC resonator the output was not what i expected although the ADS simulations was fine before putting it, the resonator center frequency is 950MHz . i have calculated its frequency range after putting the varactor:
Min.Freq.=934MHz -- Max.Freq.=972.95MHz -- Tuning Range= 4.325250MHz/V

in the calculations the varactor was in parallel with C4 and they are in series with C1,C2,C5,C6, i am using MA46506 varactor where Rs is not mentioned in the datasheet, i took it 0.75 in the model.

 

[xtasa]

Re: Varactor tuning

Hello Redhat,

What is your question?

XTASA

 

[redhat]

Re: Varactor tuning

Hello xtasa,
sorry, is it right to take the varactor in parallel with C4 and they are in series with C1,C2,C5,C6 to calculate the total capacitance?

 

[vagarwal]

Re: Varactor tuning

i think placing the varactor in parallel to another capacitor reduces its tuning range...