A varactor is a semiconductor device whose reactance may be varied by applying a bias volt...

A varactor is a semiconductor device whose reactance may be varied by applying a bias voltage. The quality factor can be expressed3 as

whereCJ is the junction capacitance (which depends on the voltage applied to the device), Rs is the series resistance of the device, andRp is an equivalent parallel resistance term, (a) If C_J = 3.77 pF at 1.5 V, RP = 1.5 MΩ, and Rs = 2.8 Ω, plot the quality factor as a function of frequency ω. (b) Differentiate the expression for Q to obtain both ω and Qmax.