A low noise amplifier (LNA) is used to boost very weak RF signals received by a receiver without degrading the signal-to-noise ratio. It is commonly the first component in a receiver and amplifies the signal sufficiently above the noise floor to allow for further processing. The LNA directly impacts the receiver's sensitivity, with ideal characteristics including low noise figure, sufficient gain, appropriate bandwidth, and good linearity. Common LNA types are BJT and MOSFET, with BJT having higher gain but also higher power consumption. LNA performance is measured by metrics such as noise figure, gain, bandwidth, and linearity. LNAs are essential components in communications systems using radio signals.