Patent ID: 7174147

Claim:
A tunable bandpass filter comprising: a first ferroelectric (FE) tank circuit comprising: a first node to accept an input signal; a first resonator having a first resonator input connected to the first node and a first resonator output connected to a reference voltage; and a second capacitor having a second capacitor input connected to the first node, a second capacitor output connected to the reference voltage, and a control signal input to accept a control signal, the second capacitor comprising an FE material with a dielectric constant responsive to the control signal; a second FE tank circuit comprising: a second node to supply a bandpass filtered signal; a second resonator having a second resonator input connected to the second node and a second resonator output connected to the reference voltage; and a third capacitor having a third capacitor input connected to the second node, a third capacitor output connected to the reference voltage, and a second control signal input to accept a second control signal, the third capacitor comprising a second FE material with a second dielectric constant responsive to the second control signal; and a first capacitor connected in series between the first node and the second node.