US Patent 8644773 Multiband low noise amplifier (LNA) with parallel resonant feedback

A multiband low noise amplifier (LNA) with parallel resonant feedback includes an amplifier element configured to receive a radio frequency (RF) signal at an RF input and provide an amplified version of the RF signal at an RF output, a resistive feedback circuit coupled between the RF input and the RF output, and a plurality of series-coupled resonant circuits coupled in series with the resistive feedback circuit between the RF input and the RF output of the amplifier element, wherein each of the resonant circuits is configured to operate as an effective short circuit at a frequency other than a resonant frequency and configured to operate as an effective open circuit at the resonant frequency to decouple the resistive feedback from the amplifier element at each resonant frequency.