Between source node and ground,there is a network constructed by an inductor in series with a capacitor.If the inductor-capacitor network has a resonance frequency in operation band, it can supress the outband gain,improve the stability and widen the operation band。
Is it possible?
acctually, it is a self-bias structure for the fet, and it can provide a negative Vgs. The capacitor is a bypass capacitor. My another explaination is that the inductor(strip-line) has a function of negative feedback(current-voltage feedback), according to the character of feedback, it can absolutely widen the band.
yes,the resistor will increase the noise more or less, it is the shortcoming of self-bias. But it has a notable advantage of operation with a sigle power supply.
I think the bypass capacitor can reduce the resistor's effection