Patent ID: 7786806

Claim:
A method of amplifying a received input signal with substantially constant gain over a wide frequency range, comprising: tuning a narrow-band cascode amplifier to amplify the received input signal only if the received input signal is within a selected partial frequency range of the wide frequency range corresponding to a signal of interest using a first variable capacitor element coupled in parallel with an inductive load, the first variable capacitor element and the inductive load being connected to a transistor of the narrow-band cascode amplifier, wherein the tuning comprises varying the first variable capacitor element using predefined values of the first variable capacitor that are stored in a control circuit; and compensating a non-linear gain response of the narrow-band amplifier according to the selected partial frequency range to achieve the substantially constant gain using a second variable capacitor element coupled in parallel with an inductor, the second variable capacitor element and the inductor being connected to another transistor of the narrow-band cascode amplifier, wherein the compensating comprises varying the second variable capacitor element using predefined values of the second variable capacitor that are stored the control circuit in a coordinated manner with the varying of the first variable capacitor element.