Comparison of three structures of low noise amplifiers and development of a filter of RF for receivers for PCS

The behavior comparison of three low noise amplifiers (LNA´s) is presented, SiCe amplifiers for personal communications systems (PCS) with inductive degeneration, cascode and with active feedback are analyzed. Their design was simultaneously made with one duplexer. The joined designs let us improve some parameters like intermodulation distortion. The construction and characterization of an amplifier with active feedback is given. It constitutes a recommendable option to be used in third generation receivers due to its dynamic stability, low noise level, great bandwidth and high linearity.